Recent itsdavis_ucprc_researchreports items

Investigation into the Use of Reclaimed Asphalt Pavement in Gap- and Open-Graded Asphalt Rubber Mixes: Phase 2: Laboratory Testing of Aggregate Replacement and CalME Simulation

Wed, 25 Mar 2026 00:00:00 +0000

This report presents data and analysis completed to evaluate changes in mix properties and simulated mix performance in pavement structures when using coarse reclaimed asphalt pavement (RAP) materials in new gap- and open-graded rubberized hot mix asphalt (HMA) (structural performance for gap-graded mixes only) and to prepare recommendations and suggested specification language, if considered appropriate, for allowing the use of coarse RAP in gap- and open-graded rubberized hot mix asphalt. This report includes laboratory binder and mix testing, as well as CalME fatigue and reflective cracking simulation results for four plant-produced gap-graded rubberized hot mix asphalt (RHMA-G) mixes used on the Heavy Vehicle Simulator test track at the UCPRC. The four mixes had the same base binder and two aggregate gradations, both with and without RAP. Six laboratory-produced mixes were also tested, using rubberized binders from two field projects and two RAP sources. Three mixes were...

Evaluation of Sustainable and Cost-Effective Concrete Pavement Life

Thu, 12 Mar 2026 00:00:00 +0000

Caltrans jointed plain concrete pavements (JPCP) and continuously reinforced concrete pavements (CRCP) are currently designed for a 40-year life (based on 10% fatigue transverse cracking and 10 punchouts per mile criteria, respectively). While this is already a long-life design, there is the concern that it may not result in the minimum possible life cycle cost and environmental impacts. The current Caltrans Highway Design Manual (HDM), including the Rigid Pavement Design Catalog, and the Standard Specifications applicable to concrete pavements, are based on this 40 year design life. This study includes recommendations for the materials, design, and construction of concrete pavements aimed at extending the design life up to 100 years. These recommendations are based on existing knowledge and tools and indicate the changes necessary to Caltrans’s existingspecifications and practices. However, uncertainties remain in traffic load and climate predictions, as well as the limitations...

Cold Central Plant Recycling Study: Preliminary Determination of Maximum Time That Processed Material Can Be Stockpiled and Compacted

Tue, 17 Feb 2026 00:00:00 +0000

The objective of this preliminary study was to investigate the effect of delayed compaction and/or stockpiling of cold central plant recycled materials with foamed asphalt recycling agents and cement active fillers. The results are also considered applicable for emulsified asphalt recycling agents and in-place cold recycling. Given that hydrated lime is currently not permitted as an active filler for cold recycled materials in Caltrans specifications, no tests were conducted with lime, and no recommendations are made regarding stockpile time if lime is considered in the future. A separate study will need to be completed for lime if justified.

The following conclusions were drawn from the test results: (1) delayed compaction or stockpiling results in reduced material workability—characterized by lower densities, strengths, and stiffnesses—which in turn will result in shorter pavement life, (2) delayed compaction or stockpiling can further increase variability in terms...

Update of the PG Binder Map in California Using the Enhanced Integrated Climate Model (EICM) and LTPPBind Online

Wed, 19 Nov 2025 00:00:00 +0000

Nine climate regions in California for mechanistic-empirical pavement design were identified in 2005 using data from weather stations in the National Climatic Data Center (NCDC) from 1961 to 1990, along with data from the Climatic Database for Integrated Model from 1976 to 1995. The climate data were analyzed using the Enhanced Integrated Climatic Model (EICM) software to predict pavement temperatures at different depths, including 28 different flexible pavement structures. For asphalt pavement, the most important environmental variable is temperature. The 2005 climate region map also included asphalt binder performance grades (PG) for each climate region, developed using EICM and Long-Term Pavement Performance (LTPPBind) (v.2.0), resulting in four different PG grades for the nine regions. The number of PG grades was reduced from a larger number identified by the PG binder grade specification criteria to simplify the number of grades that would need to be produced in the state.

This...

Feasibility of Cold Central Plant Recycling Asphalt Mixtures for Airports: Task 1 Report

Thu, 6 Nov 2025 00:00:00 +0000

This report summarizes the work completed in Phase 1 of a study to investigate the feasibility of using cold central plant recycled (CCPR) asphalt mixtures on airport pavements. Tasks within this phase included a literature review, laboratory and limited accelerated wheel load testing, development of a procedure for designing airport pavements that include a recycled layer, development of test plans for accelerated pavement testing at the FAA’s William J. Hughes facility, development of specifications for constructing the cold central plant recycled layers on the test track, and development of just-in-time training for all personnel participating in the construction of the test track. The specifications and just-in-time training deliverables will be revised for general use based on observations and feedback from construction of the test track.

The primary conclusions from the study include the following: (1) there is limited published literature on the use of cold recycled...

Cold Recycling Study: Testing to Develop Standard Mix Design and Quality Control/Quality Assurance Testing Procedures for Cold Recycling Project Specifications (Metric Units)

Tue, 5 Aug 2025 00:00:00 +0000

This report summarizes the research to evaluate cold recycling mix design procedures and to standardize specifications for cold recycling. The study focused on a review of different test methods for specimen compaction and strength testing and different specification limits for emulsified and foamed asphalt. Important findings from the study include the following: (1) specimen densities from Marshall compaction are higher than gyratory compaction and nuclear gauge field densities, (2) gyratory compaction using 30 gyrations is typically marginally higher than field density, (3) indirect tensile strength (ITS) and stability are strongly correlated to density, (4) mix designs done with Marshall compaction may underestimate binder and cement content requirements, (5) using Marshall compaction to compact specimens for quality control testing can result in strengths that are not representative of those on the road (i.e., higher), thereby potentially meeting the passing requirement in...

Cold Recycling Study: Testing to Develop Standard Mix Design and QualityControl/Quality Assurance Testing Procedures for Cold Recycling Project Specifications (Imperial Units)

Tue, 5 Aug 2025 00:00:00 +0000

This report summarizes the research to evaluate cold recycling mix design procedures and to standardize the specifications for cold recycling in California. Questions were developed based on a review of relevant test methods surrounding the options for specimen compaction and the difference in strength testing method and specification limits for emulsified asphalt and foamed asphalt. Important findings from the study include the following:• Specimen densities from Marshall compaction are higher than gyratory compaction and field densities measured with a nuclear gauge and corrected for gravimetric moisture content.• Gyratory compaction using 30 gyrations is typically marginally higher than field density.• Indirect tensile strength (ITS) and stability are strongly correlated to density.• Mix designs done with Marshall compaction may underestimate binder and cement content requirements.• Using Marshall compaction to compact specimens for quality control testing can result in strengths...

Cold Central Plant Recycling Study: First-Level Analysis of Heavy Vehicle Simulator Testing

Mon, 4 Aug 2025 00:00:00 +0000

This first-level analysis research report summarizes the construction and instrumentation of a test track to study the behavior of cold recycled layers containing 100% recycled asphalt pavement (RAP) materials in a pavement structure (recycled in place or through a central plant), a first-level analysis of the results from six Heavy Vehicle Simulator (HVS) tests, and a forensic investigation. The six HVS tests covered three recycling agents, testing at two pavement temperatures (30°C [86°F] and 50°C [122°F] at 50 mm [2 in.] depth), and two moisture conditions (as-compacted and under constant water flow). The same loading program was followed on all sections, and testing was continued until either terminal rut (12.5 mm [0.5 in.]) or terminal cracking (2.5 m/m2 [0.76 ft./ft2]) was reached. A review of all HVS test data, together with observations from the forensic investigation, indicates that localized shear failures in the aggregate base after heavy rainfall and issues associated...

100% RAP Pilot Project on SBD 40: Material Testing, Life Cycle Assessment, Observations, and Findings

Fri, 16 May 2025 00:00:00 +0000

This report presents data and analysis of a new mix type that has 100% replacement of aggregate and asphalt binder with reclaimed asphalt pavement (RAP) and the addition of a recycling agent. The data were collected from construction of a pilot project on Interstate 40 in San Bernardino County, which included the new mix , HyRAP® (a registered trademark owned by Brooks Construction Company, Inc. and licensed to Manhole Adjusting Inc. but produced under a non-proprietary Caltrans Non- Standard Special Provision), the control gap-graded rubberized hot mix asphalt (RHMA-G), and a dense-graded polymer- modified mix (HMA-M) that was used in wheelpath digouts on the project. The report includes performance-related testing, a life cycle assessment, and a summary of observations from the construction of the pilot project. It also includes deflection testing results for the test sections and outside the test sections to check if they have similar underlying support. The life cycle assessment...

Final Noise and Smoothness Monitoring on Concrete Pilot Projects of Grind and Groove and Continuously Reinforced Concrete Pavements

Wed, 30 Apr 2025 00:00:00 +0000

The goal of this report is to conclude the project titled “Quieter Pavement Long-term Monitoring” by completing the measuring of noise and smoothness on previously built jointed plain concrete pavements (JPCP), surfaced with conventional diamond grinding (CDG) or the new grind and groove (GnG), and on continuously reinforced concrete pavement (CRCP). Previous studies have initiated the investigation into both the noise properties of GnG and CRCP. This project gathered data in 2018 and again in 2020 on the performance of these concrete pavements in terms of noise and smoothness. These data were added to the noise database to further the development of specifications, guidelines, and standardized field test methods toward quieter pavements. The GnG technology on test sections in Caltrans pilot projects was evaluated in terms of measured tire/pavement noise, smoothness, friction, and surface drainability. The results of this study are to be used to further incorporate quieter pavement...

Analysis of 30 Years of Pavement Temperatures using the Enhanced Integrated Climate Model (EICM)

Wed, 26 Mar 2025 00:00:00 +0000

In this study, databases for rainfall and temperatures were developed for six climate regions of California. The weather data was obtained from National Climatic Database Center (NCDC). The pavement temperatures were simulated using Enhanced Integrated Climatic Model (EICM) software. Hourly pavement temperatures at the critical depths in the pavement layers were obtained using EICM for six cities, one in each of the identified climate regions.The objectives of the study presented in this report are:- Create a database of hourly pavement temperatures predicted using EICM for 30 years (1961-1990) for typical California pavements including hourly averages and standard deviations of pavement temperatures for each of the six California climate regions.- Evaluate the stability of pavement temperatures and rainfall across different 5-year periods to determine whether 5 years of data is sufficient to characterize a climate region.- Qualitatively evaluate the effects of pavement temperatures...

Climate Regions for Mechanistic-Empirical Pavement Design in California and Expected Effects on Performance

Wed, 26 Mar 2025 00:00:00 +0000

Chapter 2 contains an outline of the methodology of this study. The methodology includes a characterization of the climates studied, a brief introduction to the software used to estimate pavement temperatures, and an outline of assumptions. Chapter 3 presents analysis of the pavement temperature and thermal gradient data. The analysis is organized according to pavement type and distress type. Chapter 4 presents an overview of the rainfall data. Chapter 5 presents the conclusions drawn from the data analysis and recommendations for inclusion of the results in current Caltrans operations and in the mechanistic-empirical design procedure being developed for Caltrans by the University of California Berkeley Contract Team.

Goal 4 Long Life Pavement Rehabilitation Strategies—Rigid: Laboratory Strength, Shrinkage, and Thermal Expansion of Hydraulic Cement Concrete Mixes

Wed, 26 Mar 2025 00:00:00 +0000

This report presents the results of laboratory work on flexural and compressive strength, free shrinkage, coefficient of thermal expansion, and elastic modulus performed on six concrete mixes. The six concrete mixes are typical of those used, or have been considered for use, for the Caltrans Long Life Pavement Rehabilitation Strategies for rigid pavements (LLPRS-Rigid).

The work presented in this report was completed as part of Goal 4 of the Partnered Pavement Research Program Strategic Plan, and completes the following objectives of the test plan for that research goal: - -

- Evaluation of, and development of recommendations for test methods for strength gain, ultimate strength and stiffness, thermal expansion, and shrinkage.

- Development of laboratory data regarding the properties of various high earlystrength concrete mixes, and comparison with a typical Type I/II mix.

- Development of laboratory data regarding the effects of important mix design...

Performance of Drained and Undrained Flexible Pavement Structures in Accelerated Loading Under Wet Conditions–Summary Report Goal 5 Partnered Pavement Performance Program

Wed, 26 Mar 2025 00:00:00 +0000

The California Department of Transportation (Caltrans) requires that all new flexible pavements include a 75-mm layer of asphalt treated permeable base (ATPB) between the asphalt concrete and the aggregate base layers. The purpose of the ATPB layer is to intercept water entering the pavement because of high permeability resulting from insufficient compaction or through cracks in the asphalt concrete layer and transport it away from the pavement before it reaches the unbound materials.This reports summarizes the results of a study using Heavy Vehicle Simulator (HVS) trafficking to evaluate the performance of drained and undrained flexible pavements under wet (saturated base) conditions. A drained structure is a pavement section that contains an ATPB layer between the asphalt concrete and the aggregate base. An undrained structure is a pavement section that does not contain an ATPB layer. Wet conditions used in this study were intended to simulate approximate surface infiltration...

Stiffness, Strength, and Performance of Unbound Aggregate Material: Application of South African HVS and Laboratory Results to California Flexible Pavements

Wed, 26 Mar 2025 00:00:00 +0000

Caltrans specifies the use of a 75-mm Asphalt Treated Permeable Base (ATPB) layer as standard practice for all new flexible pavement designs in California.(1) The ATPB acts as a drainage layer beneath the asphalt concrete (AC) and is supported by an aggregate base layer. However, the potential exists for water to enter the unbound aggregate base layer from the ATPB layer through the prime coat that separates them. The stiffness, strength, and performance of unbound aggregate layers are largely influenced by moisture content.The assessment of the performance of two types of flexible pavement cross section, one with and one without an ATPB layer, were included in the strategic plan of the CAL/APT program (1994-2000). Goal 1 and Goal 5 of the CAL/APT project (continued in the Partnered Pavement Research Program after 2000) consist of the evaluation of these two sections under dry and wet base conditions, respectively.The evaluation includes accelerated pavement testing using the...

Accelerated Laboratory Testing for Alkali-Silica Reaction Using ASTM 1293 and Comparison with ASTM 1260

Wed, 26 Mar 2025 00:00:00 +0000

A great deal of work on alkali-silica reactivity (ASR) has been reported since1940. ASR is a reaction in which certain aggregates react with the highly alkaline pore solution of concrete. As the name of the reaction implies, the reactive aggregate contains silica. However, not all siliceous aggregates are reactive.In general, the aggregates that cause harmful reactions in concrete are those containing amorphous silica (glasses and opal), unstable crystalline polymorphs of silica (cristobalite and tridymite), poorly crystalline forms of silica (andesite and rhyolite), and microcrystalline quartz-bearing rocks (quartzite and greywacke). The highly alkaline pore fluids of concrete are able to depolymerize the reactive silica present in the aggregates, forming products of different compositions in the concrete pores. In the presence of moisture, the reaction products (gel products) change in volume and may expand to such a degree that the concrete tensile strength is reached and the...

Performance of Drained and Undrained Flexible Pavement Structures Under Wet Conditions – Accelerated Test Data, Test Section 545–Undrained

Wed, 26 Mar 2025 00:00:00 +0000

This report is the third in a series that describes the results of accelerated pavement testing conducted on full-scale pavements at the Richmond Field Station (RFS). The report contains a summary of the results and associated analyses of a pavement section composed of three lifts of asphalt concrete and an untreated aggregate base layer on top of a prepared subgrade. The pavement section is termed an undrained pavement because it does not include an ATPB layer between the asphalt concrete layers and the untreated aggregate base. The pavement structure was designated Section 545. The tests on this test section have been performed as part of the Goal 5 Accelerated Test Program for the evaluation of drained and undrained pavements under conditions of water infiltration. The main objective of the test program is to develop data to quantitatively compare and evaluate the performance of reduced thickness asphalt rubber hot mix (ARHM) and full thickness of dense graded asphalt concrete...

CAL/APT Program – Construction of the Goal 3 Overlays and Recommendations for Improved Overlay Performance in California

Wed, 26 Mar 2025 00:00:00 +0000

This report describes the construction of the CAL/APT Goal 3 overlays and details observations regarding current Caltrans procedures which are intended to help improve the performance of Caltrans overlays. The main objective of Goal 3 is the comparison of the performance of a Gap Graded Asphalt Rubber Hot Mix (ARHM-GG) overlay with that of a conventional Dense Graded Asphalt Concrete (DGAC) overlay. Based on Caltrans design procedures, ARHM-GG overlay thicknesses are typically half of the equivalent DGAC overlay. These overlays represent typical pavement structures currently in use throughout California (1). The complete plan for HVS and laboratory testing and associated analyses is outlined in the Goal 3 test plan (9).

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Asphalt Treated Permeable Base (ATPB)–Section 502CT

Wed, 26 Mar 2025 00:00:00 +0000

This report is the third in a series which describe the results of tests and their interpretation on full-scale pavements designed and constructed according to the procedures of the California Department of Transportation (Caltrans) at the Richmond Field Station (RFS) of the University of California at Berkeley (UCB). It describes the results of the Heavy Vehicle Simulator (HVS) test on the third of four pavement test sections, an asphalt-concrete section containing an asphalt treated permeable base (ATPB) designated Section 502CT. The tests on these four test sections have been performed as part of Goal 1 of the Strategic Plan of the Caltrans Accelerated Pavement Testing, or CAL/APT program (1).

Analysis of Sensitivity of Plain Jointed Concrete Pavement in California to Early-Age Cracking Using HIPERPAV

Wed, 26 Mar 2025 00:00:00 +0000

The work included in this report completes the first of the three objectives of the earlyage cracking investigation plan. This report also presents preliminary recommendations for the use of HIPERPAV and for the mitigation of early-age cracking based on the HIPERPAV sensitivity analysis.

Normalizing the Behavior of Unsaturated Granular Pavement Materials

Wed, 26 Mar 2025 00:00:00 +0000

One of the important components of a flexible pavement structure are granular material layers. The unsaturated granular pavement materials (UGPMs) in these layers influence stresses and strains throughout the pavement structure, and can have a large effect on asphalt concrete fatigue and pavement rutting, which are two of the primary failure mechanisms for flexible pavements. The behavior of UGPMs is highly dependent on water content, but this effect has been traditionally difficult to quantify using either empirical or mechanistic methods.This report presents a mechanistic framework for normalizing the behavior of UGPMs within the range of water contents, densities, and stress states likely to be encountered under field conditions. Both soil suction and generated pore pressures are calculated and compared to applied confinement under typical field loading conditions. The framework utilizes a new soil suction model that has three density-independent parameters, and can be determined...

Assessing the Economic Benefits from the Implementation of New Pavement Construction Methods

Wed, 26 Mar 2025 00:00:00 +0000

This report is organized in the following way: Section 2 provides a brief overview of the current state of the art in road building technologies and methods. The new methods of road building and maintenance that are being advocated are described in detail in Section 3. In Section 4, the attributes of the sample of roadway sections selected for analysis are identified and the methodology is described. Section 5 compares the differential costs of old and new approaches to pavement technologies as well as discusses calculations of the projected savings to Caltrans if it were to adopt the new approach as standard practice in roadway maintenance and rehabilitation. Section 6 contains estimates of the differential returns from the application of different types of new pavement technology including, increased compaction, use of a tack coat, and use of a rich bottom layer. Section 7 contains the summary and conclusions.

Analysis and Estimation of Effective Built-In Temperature Difference for North Tangent Slabs: Data Analysis from the Palmdale, California Rigid Pavement Test Site

Wed, 26 Mar 2025 00:00:00 +0000

As part of the California Department of Transportation (Caltrans) Long Life Pavement Rehabilitation Strategies (LLPRS), a high early strength hydraulic cement was field tested using the Heavy Vehicle Simulator (HVS). This fast-setting hydraulic cement concrete (FSHCC) was designed to gain enough strength to allow it to be opened to traffic within 4 hours of placement. The objective of the HVS tests was to evaluate the performance of this concrete under the influence of simulated loads along with pavement design features such as dowels, tied concrete shoulder, and a wide truck lane that had not previously been implemented in California.Two full-scale test pavements, each approximately 700 ft. (215 m) in length, were constructed on State Route 14 about 5 miles (8 km) south of Palmdale, California using FSHCC. The South Tangent was constructed along State Route 14 southbound and was used to conduct a fatigue evaluation of the FSHCC with three thicknesses of PCC [4, 6, and 8 in. (100,...

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Untreated Aggregate Base–Section 503RF

Wed, 26 Mar 2025 00:00:00 +0000

This report is the fourth in a series which describe the results of tests and their interpretation on full-scale pavements constructed at the Richmond Field Station (RFS) which have been designed and constructed according to Caltrans procedures. It describes the results of the Heavy Vehicle Simulator (HVS) test on the fourth of four pavement test sections, an asphalt-concrete section containing an untreated aggregate base designated Section 503RF. The tests on these four test sections have been performed as part of Goal 1 of the CAL/APT Strategic Plan.

Shrinkage and Thermal Cracking of Fast Setting Hydraulic Cement Concrete Pavements in Palmdale,California

Wed, 26 Mar 2025 00:00:00 +0000

Jointed Plain Concrete Pavement (JPCP) test sections were constructed using Fast Setting Hydraulic Cement Concrete (FSHCC) as part of the California accelerated pavement testing program (CAL/APT). Many of the longer slabs cracked under environmental influences before any traffic load was applied to them. Cores drilled through the cracks indicated that cracking initiated at the top of the slabs and propagated downwards. Concrete shrinkage and thermal strain data from field instrumentation was recorded and analyzed along with laboratory test data to determine the cause of the cracking. Finite element analysis using the measured strains and temperatures predicted high tensile stresses at the top of the test section slabs as a result of the differential drying shrinkage between the top and base of the slab and the non-linear nature of the negative temperature gradients through the slab. Laboratory free shrinkage tests on the test section cement indicated significantly higher shrinkage...

Accelerated Laboratory Testing for High Early StrengthConcrete for Alkali Aggregate Reaction

Wed, 26 Mar 2025 00:00:00 +0000

Aggregate makes up a significant portion of concrete. However, unlike cement, there are limited choices as to the composition and source of aggregate to be used. It has been shown in the laboratory and in the field that certain types of aggregate can cause deleterious expansion through a reaction known as alkali-silica reaction (ASR). In order to ensure the durability of new pavements and projects, the susceptibility of aggregates and cements need to be investigated. An accelerated test for ASR susceptibility was used in which mortar bar length changes were measured and used to indicate the potential of being reactive. Aggregate consisting of granite, mylonite, phyllonite, and ultramylonite were tested. These aggregates have the same chemical and mineralogical composition, however they all have differences in grain size. For the samples studies, smaller grain size indicated a higher amount of deformation. Two aggregate types were chosen for which the different types of cements...

Evaluation of the Maturity Method for Flexural Strength Estimation in Concrete Pavement

Wed, 26 Mar 2025 00:00:00 +0000

The primary purpose of the work presented in this report is to provide Caltrans with information regarding the accuracy and feasibility of the maturity method for the measurement of concrete flexural strength. Information is also provided regarding use of the maturity method for measurement of compressive strength.

Palmdale South Tangent Slab Built-In Curling and Cracking: Preliminary Analysis Report

Wed, 26 Mar 2025 00:00:00 +0000

This report presents a preliminary analysis of slab cracking at the South Tangent sections tested at Palmdale, California using the Heavy Vehicle Simulator (HVS). The data collected on the South Tangent include corner and edge deflections, thermocouple data representing temperature distribution through the slabs, visual and photographic crack surveys, crack activity measurement data, multi-depth deflection data representing deflections at various depths beneath the pavement surface, slab strains measured at critical locations using strain gages, and falling weight deflectometer (FWD) data. The primary focus of this report is the preliminary cracking analysis of the South Tangent slabs. The chief tool used in this analysis is the finite element program, ISLAB2000, which is used to estimate pavement responses for a given geometry under the influence of wheel loadings and layer temperature profiles. The key data used in the analysis include measured corner deflections, thermocouple...

Rutting of Caltrans Asphalt Concrete and Asphalt-Rubber Hot MixUnder Different Wheels, Tires and Temperatures – AcceleratedPavement Testing Evaluation

Wed, 26 Mar 2025 00:00:00 +0000

This report presents results from accelerated pavement tests using the Caltrans Heavy Vehicle Simulator (HVS) of DGAC and ARHM-GG overlays placed at the University of California, Berkeley Pavement Research Center. The results in this report are from tests conducted at elevated temperatures to evaluate the rutting performance of the two overlay strategies. The tests also investigated the effects of tire type, temperature and thickness of the ARHM-GG overlay. The overlays were placed on existing flexible pavement structures, sections of which were previously tested as part of CAL/APT Goal 1 (5-9). The mix designs and thickness designs for the overlays and their construction are included in References (10, 11).

HVS Test Results on Fast-Setting Hydraulic Cement Concrete, Palmdale, California Test Sections, South Tangent

Wed, 26 Mar 2025 00:00:00 +0000

As part of the Caltrans Long Life Pavement Rehabilitation Strategies (LLPRS), a fast setting strength hydraulic cement concrete (FSHCC)/Type I/II portland cement concrete (PCC) blend was evaluated under Heavy Vehicle Simulator (HVS) tests as detailed in the Test Plan for CAL / APT Goal LLPRS - Rigid Phase III (1). Because it is expected to be used on projects where heavy trucks are expected to be allowed on the slabs within 4 to 8 hours after placement, this newly placed concrete is specified to obtain a flexural strength of 2.8 MPa within 4 to 8 hours of placement. Two full-scale test sites, each approximately 210 m in length, were constructed using this concrete on either side of State Route 14 about 5 miles south of Palmdale, California. Various test sections were constructed at these two sites. The site in the southbound direction included sections with different thicknesses of concrete placed on compacted granular base. The site in the northbound direction included 200-mm...

Performance of Caltrans Asphalt Concrete and Asphalt-Rubber Hot Mix Overlays at Moderate Temperatures—Accelerated Pavement Testing Evaluation

Wed, 26 Mar 2025 00:00:00 +0000

This report presents results from accelerated pavement tests using the Caltrans Heavy Vehicle Simulator (HVS) of DGAC and ARHM-GG overlays placed at the University of California Berkeley Pavement Research Center. The results presented in this report are from four tests conducted at 20 degrees C to evaluate the performance of the two overlay strategies with respect to cracking (fatigue or reflection), and rutting of the unbound pavement layers. Both overlay strategies were evaluated on previously tested drained and undrained flexible pavement structures. The overlays were placed on existing flexible pavement structures, sections of which were previously tested as part of CAL/APT Goal 1. The mix designs and thickness designs for the overlays and their construction are included in References (10, 11).

Data Mining of the Caltrans Pavement Management System (PMS) Database

Wed, 26 Mar 2025 00:00:00 +0000

Since 1977, Caltrans has been routinely collecting performance information for its pavement network and using a pavement management system (PMS) to manipulate this information in order to aid in the management of the network. This report details the "mining" of this database to extract environmental performance indicators for the various climate regions in California, and to extract section information for portland cement concrete (PCC) pavements that have been overlaid with asphalt concrete (with the specific goal of obtaining information regarding the reflection cracking performance). The first objective of this study is to provide the best possible estimate of the performance of the standard Caltrans strategy for asphalt concrete overlays of PCC pavements, to provide an estimate to Caltrans, and to provide calibration data for the development of mechanistic-empirical models for reflection cracking. The second objective of this study is to provide recommendations for short-term...

Constructability and Productivity Analysis for Long Life Asphalt Concrete Pavement Rehabilitation Strategies

Wed, 26 Mar 2025 00:00:00 +0000

A large portion of the highway system in the United States has exceeded its design and its service life. Deterioration of the existing highway system adversely affects the safety of road users, ride quality, the operational cost of vehicles, and the cost of highway maintenance. This report presents the results of a constructability and productivity analysis for the Caltrans Long Life Asphalt Concrete Pavement Rehabilitation Strategies (LLACPRS), focusing on optimizing the maximum production capability within a 55-hour weekend closure.With the assistance of California asphalt concrete paving contractors, the constructability analyses explored the effects of the following parameters: rehabilitation materials, design profile [Crack Seat and Overlay (CSOL) and Full-Depth Asphalt Concrete (AC) replacement of different thickness], cooling time, number and capacity of construction resources, and alternative lane closure strategies. The experiment design consisted of a hierarchical structure...

Life Cycle Assessment of Asphalt Binder, Warm Mix Asphalt Additives, and Bonded Concrete Overlay of Asphalt for California Conditions

Fri, 28 Feb 2025 00:00:00 +0000

The UCPRC is updating and expanding the life cycle inventories (LCIs) that are available for materials, pavements, and practices being used in or introduced to California for use in the project-level design software, eLCAP, and in the Caltrans pavement management system,PaveM. This report presents the results of developing LCI for use in life cycle assessment (LCA) for three types of materials or pavement structures being used in California: (1) asphalt binder regionalized to California from a national average, (2) warm mix asphalt (WMA) technologies, and (3) bonded concrete overlay of asphalt (BCOA). These LCIs fill important gaps because asphalt binder environmental product declarations (EPDs) will not be available for several years and very few WMA EPDs are available. The results of the binder LCI showed that California has a typical asphalt binder global warming (GW) of 0.456 kgCO₂ eq/kg of binder compared to Petroleum Administration for Defense...

Impact of Silo Storage on the Performance of Plant-Produced Mixes Containing High Content of Reclaimed Asphalt Pavement or Reclaimed Asphalt Shingles

Fri, 28 Feb 2025 00:00:00 +0000

Use of recycled materials, such as reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS), is gaining widespread interest. Currently the California Department of Transportation standard specifications do not allow the use of RAS and limit the use of RAP contents to a maximum of 25% by dry weight of aggregate, though there is a non-standard special provision that allows use of up to 3% RAS by mass of aggregate and 40% RAP content by binder replacement. Nevertheless, mixes with high RAP and RAS are being produced across California for local agencies and commercial use. This study investigated the performance of four plant-produced high RAP or RAS mixes collected from different regions in California. The mixes were not designed and produced following Caltrans specifications. However, they provide insight into the effects of silo storage time on blending of virgin and RAP binder, the performancerelated properties of these mixes, and the measurement of properties by...

Pavement ME JPCP Transverse Cracking Model Calibration and Design Catalog Framework (Version 2.5.5)

Fri, 28 Feb 2025 00:00:00 +0000

The Mechanistic-Empirical Pavement Design Guide (MEPDG) is a comprehensive method, including models and guidance, developed in 2002 by the American Association of State Highway and Transportation Officials (AASHTO) to analyze and design both flexible and rigid pavements. The MEPDG is implemented in a software called Pavement ME. The MEPDG models were calibrated using data from the Long-Term Pavement Performance (LTPP) sections from throughout the United States, including some from California. The MEPDG recommends that nationally calibrated models be validated using local data and, if necessary, recalibrated. This recommendation is particularly applicable to the Caltrans road network, considering the climate and materials differences between California and the rest of the nation. The first step in recalibrating Pavement ME is to perform a sensitivity analysis to identify which variables are most important and to look for results that do not match expected performance. This was...

Development of Performance-Based Specifications for Asphalt Rubber Binder: Phase 2g Testing of Plant-Sampled Binders and RHMA-G Mixes

Thu, 27 Feb 2025 00:00:00 +0000

The work discussed in this interim report is part of a larger study, funded by the California Department of Transportation. The study objective focuses on developing and recommending testing procedures and criteria for performance-based specifications of asphalt rubber binders used in gap-graded and open-graded mixes using current Superpave performance grade (PG) equipment. Work in this phase covered the testing of 19 plant-produced binders and the base binders used to produce them. Plant-produced gap-graded rubberized hot mix asphalt mixes from five of the projects were also tested. The following important observations from the binder rheology tests were made:

--Although the low-temperature performance grades appeared to be reasonable, the high-temperature grades appeared to be unrealistically high, while the intermediate-temperature grades appeared to be potentially lower than anticipated, when comparedto the base binders. Fourteen of the binders tested with concentric...

Analysis of Recycling Agent Effects on the Mechanical Properties of HMA with High Recycled Binder Ratios

Mon, 16 Dec 2024 00:00:00 +0000

The goal of the research presented in this report is to study how the mechanical properties of hot mix asphalt change upon the addition of high contents of reclaimed asphalt pavement (RAP) and the inclusion of any amount of recycled asphalt shingles (RAS), with between 25% and 50% binder replacement and to consider the addition of recycling agents to reduce the increase in stiffness and corresponding decrease in fatigue resistance. To achieve this goal, 16 mixes and the corresponding binders were fabricated and tested in the laboratory. The mix factorial includes a control gradation, two virgin binders (PG 64-16 and PG 58-28, from different sources), two RAPs with different levels of aging (PG high temperatures of 102°C and 109°C), one RAS, and two recycling agents (a petroleum-derived aromatic and a tall oil). The testing of the binders included performance grade (PG), shear stiffness, and Fourier transform infrared spectroscopy. The testing of the mixes included stiffness, four-point...

Pavement Recycling: Shrinkage Crack Mitigation in Cement-Treated Pavement Layers—Phase 2b Laboratory Testing and Performance Modeling

Fri, 26 Apr 2024 00:00:00 +0000

The California Department of Transportation (Caltrans) has been using full-depth recycling (FDR) as a pavement rehabilitation strategy since 2001. Early projects were recycled with foamed asphalt and cement. Cement-only treatments were permitted from 2015 to improve the properties of more marginal materials. However, shrinkage cracking associated with the hydration and curing of the cement-treated layers remains a concern, especially with regard to crack reflection through asphalt concrete surfacings and the related problems caused by water ingress.Crack mitigation has been studied for decades, and a range of measures related to improved mix designs and construction practices have been implemented by road agencies. One of the most promising measures, used in conjunction with appropriate mix designs, is that of microcracking the cement-treated layer between 48 and 72 hours after construction. In theory, this action creates a fine network of cracks in the layer that limit or prevent...

Drying Shrinkage Response of Full-Scale Thin Concrete Overlay on Asphalt Sections

Thu, 28 Mar 2024 00:00:00 +0000

Moisture-related shrinkage is regarded as one of the phenomena that has the largest impacts on the performance of jointed plainconcrete pavements. Still, most mechanistic-empirical design methods oversimplify or ignore predictions of moisture-relatedshrinkage and its effects on concrete pavements. This study evaluates how moisture-related shrinkage accumulates in concretepavements and the structural response of the concrete pavement slabs to the shrinkage action. The experimental data comefrom six thin concrete overlay of asphalt pavements that were instrumented with sensors to measure the structural andhygrothermal response of the slabs due to temperature and moisture-related actions. After an analysis of the predictions madeby current shrinkage models, a new shrinkage model was developed. This new model, which is based on the incremental-recursive application of the B4 shrinkage model, provided an excellent prediction of the moisture-related shrinkage measured inthe field. In...

Preliminary Study on Developing a Surrogate Performance-Related Test for Fatigue Cracking of Asphalt Pavements

Tue, 18 Jul 2023 00:00:00 +0000

Currently, no performance-related test exists for fatigue cracking for use in routine asphalt mix design to approve job mix formula (JMF) and quality control and quality assurance (QC/QA) in California. The existing four-point bending (4PB) test was developed to evaluate the fatigue performance of asphalt pavement, but it is not necessarily appropriate for use in routine JMF and it is too slow for QC/QA. The objective of this study is to evaluate potential surrogate fatigue performance-related testing methods and identify a test that is simple and easy to perform but also able to provide guidance for asphalt mix design on routine projects and QC/QA on all projects. This report compares potential performance-related tests with 4PB tests for simplicity, repeatability (variability), and their relationship to stiffness and fatigue life. Tests evaluated in this study included the semicircular bend (SCB) test, indirect tensile asphalt cracking test (IDEAL-CT), and fatigue testing on...

Development of Performance-Based Specifications for Asphalt Rubber Binder: Interim Report on Phase 1 and Phase 2 Testing

Sun, 16 Jul 2023 00:00:00 +0000

In the United States, the Superpave Asphalt Binder Performance Grading (PG) system proposed by the Strategic Highway Research Program (SHRP) is the most common method used to characterize the performance-related properties of unmodified and polymer-modified asphalt binders. Dynamic shear modulus (G*) and phase angle (δ) are the two main binder properties and they are measured using a dynamic shear rheometer (DSR) with parallel plate geometry and either a 1-mm or 2-mm gap between the plates. Since these Superpave parameters were developed for binders that do not contain additives or particulates, the California Department of Transportation (Caltrans) does not use them for asphalt rubber binder specifications. Instead, penetration and viscosity are used as acceptance of quality control; however, these parameters do not necessarily provide a satisfactory link between the measured binder properties and potential performance in the field over a range of operating temperatures. In California,...

First-Level Analysis of Phase 1 Heavy Vehicle Simulator and Laboratory Testing on Four RHMA-G Mixes to Investigate Nominal Maximum Aggregate Size, Layer Thickness, and Performance with Aggregate Replacement from Reclaimed Asphalt Pavement

Thu, 15 Jun 2023 00:00:00 +0000

This research report summarizes a literature review update, construction of a test track to assess various aspects of gap-graded rubberized asphalt concrete (RHMA-G) mixes with and without the addition of reclaimed asphalt pavement (RAP) as aggregate replacement, a first-level analysis of the results from five Heavy Vehicle Simulator (HVS) tests, and a first-level analysis of laboratory test results on the four mixes.

Four different RHMA-G mixes were placed on seven cells on the test track at the UCPRC. Mixes differed by nominal maximum aggregate size (NMAS, 1/2 and 3/4 in.) and the addition of 10% RAP by weight of the aggregate as an aggregate replacement. Single and double lifts of each mix were placed. Apart from the addition of RAP, the mix designs all met current Caltrans specifications. Although Caltrans currently does not permit more than one lift of RHMA-G on projects, the placement of each lift of each mix on the test track met current Caltrans specifications...

Development of Performance-Based Specifications for Asphalt Rubber Binder: Phase 2g Additional Testing of Five Plant-Sampled Binders and RHMA G Mixes

Thu, 15 Jun 2023 00:00:00 +0000

The work discussed in this interim report is part of a larger study, funded by the California Department of Transportation, with the objective of developing and recommending testing procedures and criteria for performance-based specifications of asphalt rubber binders used in gap-graded and open-graded mixes using current Superpave performance grade (PG) equipment. Work covered the testing of five plant-produced binders, the base binders used to produce them, and the gap-graded rubberized hot mix asphalt mixes produced with them. The following important observations from the binder rheology tests were made:

Although the low-temperature performance grades appeared to be reasonable, the high-temperature grades appeared to be unrealistically high, while the intermediate-temperature grades appeared to be potentially lower than anticipated when compared to the base binders. A comparison of the concentric cylinder and parallel plate (3 mm gap) geometries indicated that the...

Water Quality and Toxicity Evaluation of Discharge Generated from Asphalt Pavement Surfacing Materials

Mon, 17 Oct 2022 00:00:00 +0000

Pavement engineers are constantly using new materials, such as polymer and rubber modified binders, recycled materials, and new types of asphalt mixes, such as open-graded surface courses. With their broader application, concern has been raised about the water quality of surface and subsurface runoff from modified pavement mixes used in the State of California. There are limitations in current worldwide research into runoff water quality regarding which contaminants are directly attributable to the pavement surfacing materials. This research project aims to provide that information, as part of ongoing stormwater runoff management program from the Division of Environmental Analysis of the State of California Department of Transportation (Department).

This controlled experimental study was undertaken by the Department of Civil and Environmental Engineering and the University of California Pavement Research Center (UCPRC) for the California Department of Transportation (Caltrans),...

Pavement Recycling: Shrinkage Crack Mitigation in Cement-Treated Pavement Layers — Phase 2a Literature Review and FDR-C Test Road Construction and Monitoring

Fri, 18 Mar 2022 00:00:00 +0000

The California Department of Transportation has been using full-depth recycling (FDR) as a rehabilitation strategy since 2001. Early projects were recycled with foamed asphalt and cement, but cement-only treatments were permitted from 2015 to improve the properties of more marginal materials. However, shrinkage cracking associated with the hydration and curing of the cement-treated layers remains a concern, especially with regard to crack reflection through asphalt concrete surfacings and the related problems caused by water ingress.

Considerable research has been undertaken on crack mitigation, and a range of measures related to improved mix designs and construction practices have been implemented by road agencies. One of the most promising measures, used in conjunction with appropriate mix designs, is that of microcracking the cement-treated layer between 24 and 72 hours after construction. In theory, this action creates a fine network of cracks in the layer that limit...

Investigation of the Effect of Pavement Deflection on Vehicle Fuel Consumption: Field Testing and Empirical Analysis

Tue, 15 Mar 2022 00:00:00 +0000

The results presented in this report are part of Phase II of a two-phase study. Based on the results from mechanistic models of additional fuel consumption in vehicles due to the structural response of the pavement structure, Phase I of this study concluded that pavement has a small but important enough effect on vehicle fuel consumption to warrant field investigation. The goal of the Phase II study was to measure vehicle fuel consumption in the field on different pavement types in winter and summer and at different speeds, and to use the data collected to develop empirical models for this fuel-consumption effect. The field investigation presented in this report included 21 California pavement sections with different pavement types: flexible, semi-rigid, jointed plain concrete, continuously reinforced concrete, and composite structures. The vehicles selected and instrumented for the fuel economy measurements included a five-axle semi-trailer tractor, a diesel truck, a sports utility...

Pavement ME Sensitivity Analysis (Version 2.5.3)

Tue, 15 Mar 2022 00:00:00 +0000

The Mechanistic-Empirical Pavement Design Guide (MEPDG) is a comprehensive tool developed in 2002 by the American Association of State Highway and Transportation Officials (AASHTO) to analyze and design both flexible and rigid pavements. The models in the MEPDG are implemented in software called Pavement ME, a program calibrated using Long-Term Pavement Performance (LTPP) sections from throughout the United States, including some from California. The MEPDG recommends that nationally calibrated models be validated using local data, and if necessary, recalibrated, which makes sense when considering the climate and materials differences between California and the rest of the nation. The first step in recalibrating Pavement ME is to perform a sensitivity analysis to identify which variables are most important and to look for results that do not match expected performance. The factorial for the sensitivity analysis was designed to identify sensitivity and is not the factorial to be...

Concrete Overlay on Asphalt Pilot Project at Woodland SR 113: Construction

Wed, 16 Feb 2022 00:00:00 +0000

This report documents the design and construction of a concrete overlay on asphalt (COA) pavement on State Route 113 in Woodland, California, one of the first COA projects in the Caltrans road network. The project site extended over approximately 4 mi. of a two-lane secondary road. The concrete slabs were a half-lane wide (6×6 ft.) and 6 in. thick. The transverse joints were undoweled, but tie bars were installed at all the longitudinal joints. The outside slabs were 2 ft. wider than the interior slabs to provide a concrete shoulder. The project included a section with newly placed, rubberized, gap-graded asphalt mix base. A rapid-strength concrete mixture with Type II/V portland cement designed to be opened to traffic in 24 hours was used for construction of the overlay. The northern part of the project (PM 14.760 to PM 17.580) was built in October and November 2018, while the southern part (PM 11.860 to PM 12.890) was built in April and May 2019. The concrete mixture was produced...

Increasing Crumb Rubber Usage by Adding Small Amounts of Crumb Rubber Modifier in Hot-Mix Asphalt. Phase 1: Laboratory Tests and CalME Simulations

Wed, 16 Feb 2022 00:00:00 +0000

In 2015, Caltrans expressed interest in studying the addition of small amounts of crumb rubber (CRM) in dense-graded asphalt mixes toincrease the total amount of recycled tire rubber used. Small amounts were defined as 5% to 10% CRM by weight of the binder orapproximately 0.25% to 0.5% CRM by weight of the aggregate. In this report, the terms “CRM binder” and “CRM mix” are used todenote the modified mixes. Four approaches for adding the rubber were proposed: 1) Addition of 5% to 10% CRM particles smaller than250 μm to the asphalt binder, not resulting in a change to the PG of the base binder, achieved by blending softer base binders and/orpolymers with the rubber at the refinery/terminal; 2) Addition of 5% to 10% CRM particles smaller than 2.36 mm to the asphalt binder,with allowable changes to the PG of the base binder, and produced using a field-blending process similar to that used for producingasphalt rubber binders with between 18% and 22% CRM; 3) Adding 0.25% to 0.5%...

Pavement ME Evaluation of the NCHRP 1-61 Thin Concrete Overlay on Asphalt Sections

Fri, 11 Feb 2022 00:00:00 +0000

The thin concrete overlay on asphalt (COA) longitudinal cracking model of Pavement ME was calibrated with empirical data from COA sections with half-lane width slabs in Minnesota, Illinois, and Colorado. The NCHRP Project 1-61 has considerably expanded the range of climatic conditions for which reliable performance data are available by adding projects from Iowa, Kansas, and Philadelphia (in addition to Minnesota, Illinois, and Colorado). This technical memorandum assesses Pavement ME predictions based on the longitudinal cracking measured on 13 COA sections with half-lane width slabs evaluated as part of NCHRP Project 1-61. None of the 13 sections had more than 3% of slabs with longitudinal cracking, despite four of them being subjected to relatively high traffic volumes (annual average daily truck traffic over 500 vehicles on the design lane) and having been in service between 9 and 19 years. When design values were adopted for the different input variables, Pavement ME predicted...

eLCAP: A Web Application for Environmental Life Cycle Assessment for Pavements

Wed, 9 Feb 2022 00:00:00 +0000

The California Department of Transportation (Caltrans) has a growing need to be able to quantify its greenhouse gas (GHG) emissions and the other environmental impacts of pavement operations, and to consider GHG and those other impacts in pavement management, conceptual design, design, materials selection, and construction project delivery decisions. Caltrans also needs to be able to evaluate the life cycle environmental impacts as part of policy and standards development. All these tasks can be performed using life cycle assessment (LCA), although there are different constraints and requirements with respect to the scope of the LCA and the data available for each of these different applications. The web-based software environmental Life Cycle Assessment for Pavements (eLCAP) is a project-level LCA tool that uses California- and Caltrans-specific life cycle inventories (LCIs) and processes. The LCI database has been critically reviewed by outside experts following ISO standards....

Optimizing Rubberized Open-graded Friction Course (RHMA-O) Mix Designs for Water Quality Benefits: Phase I: Literature Review

Tue, 8 Jun 2021 00:00:00 +0000

Historically, rubberized and non-rubberized open-graded friction courses (OGFCs) have been placed to provide three benefits: to increase traffic safety, to reduce urban highway noise, and to preserve the surface of the main pavement structural section. However, stringent environmental regulations on stormwater runoff management enacted recently have forced transportation agencies with limited right of ways in urban areas to search for creative methods to treat runoff and receive credits for preventing pollution from highways. This literature review was undertaken to explore ways to optimize current RHMA-O mix designs to provide multifunctional benefits, including water quality treatment. The literature review showed that permeability measurement is an essential parameter that influences a wide range of OG (both rubberized and non-rubberized) pavements’ performance. Further, current Caltrans aggregate gradations contain a larger fraction of fine aggregate sizes and this may also...

Updates to CalME and Calibration of Cracking Models

Mon, 7 Jun 2021 00:00:00 +0000

The CalME flexible pavement simulation and design software program has been completely recoded as a web-based application calledCalME 3.0. CalME 3.0 retains the same incremental-recursive damage approach and the same forms for damage models and transferfunctions as CalME 2.0, which was validated using accelerated pavement testing data from Heavy Vehicle Simulator (HVS) test sectionsand the WesTrack experiment.The following enhancements and additions are all included in the revised program. First, the old software’s fatigue cracking transferfunctions for hot mix asphalt (HMA) on aggregate base, cement-stabilized bases, and portland cement concrete have been recalibratedusing a new approach for the calibration of mechanistic-empirical pavement design methods; this approach uses “big data” frompavement management systems, explicitly and separately considers between-project and within-project variability, and uses tens tohundreds of times more performance data than are used in conventional...

Evaluation of Modified Binder Gap-Graded Mixes for Half-Thickness Reflective Cracking Overlays

Tue, 3 Nov 2020 00:00:00 +0000

The question asked by Caltrans and Industry: Will gap-graded modified binder (MB-G) mixes provide performance equal to gap-graded rubberized asphaltconcrete (RAC-G) mixes in half thickness applications? Why was this question asked?MB binders could offer cost savings, and widen the application range for rubberized binders.

Pay Factors for Asphalt-Concrete Construction: Effect of Construction Quality on Agency Costs

Fri, 30 Oct 2020 00:00:00 +0000

Contractor pay incentives serve two important objectives: 1) they encourage the paving contractor to construct pavements having decidedly superior performance in comparison to those simply meeting minimum specification requirements while, at the same time, maintaining costs at reasonable levels and 2) they provide a rational alternative for dealing with marginally inadequate/adequate construction. Many factors must be considered in the establishment of pay schedules that not only realize these objectives but are also agreeable to both contractor and highway agency alike. The approach taken herein focuses principally on economic impacts to the highway agency. It assumes that an appropriate penalty for inferior construction should be the added cost to the highway agency. It also assumes that the bonus for superior construction should be no greater than the added savings to the highway agency. Smaller maximum bonuses are likely to be necessary to insure budgetary integrity and, coupled...

Preliminary Evaluation of Proposed LLPRS Rigid Pavement Structures and Design Inputs

Fri, 30 Oct 2020 00:00:00 +0000

This report is one of four presenting preliminary findings regarding the expected performance of LLPRS strategies developed to date by Caltrans. The other reports address potential long term concrete durability problems for concrete paving materials; investigations of the effects of loading configurations, concrete strength versus traffic opening times, and xviii construction production; and the performance under HVS loading of an instrumented test pavement constructed using accelerated Portland cement concrete.

Effects of Material Properties, Specimen Geometry, and Specimen Preparation Variables on Asphalt Concrete Tests for Rutting

Fri, 30 Oct 2020 00:00:00 +0000

This report presents the results of laboratory tests and analyses performed as a part of the effort by the Federal Highway Administration (FHWA) to develop simple performance tests for asphalt concrete mix analysis and design for highway pavement applications. Three specific areas are addressed, namely: 1. The non-linearity of shape distortion (shear) properties, information required to assess the use of indirect methods to measure the shear response of asphalt mixes; 2. appropriate shape an specimen size for use in a simple performance test; and 3. comparison of mix rutting performance determined from specimens prepared using the Superpave gyratory compactor (SGC) and specimens of the same mix obtained by coring from a pavement section

Initial CAL/APT Program: Site Information, Test Pavement Construction, Pavement Materials Characterizations, Initial CAL/APT Test Results, and Performance Estimates

Fri, 30 Oct 2020 00:00:00 +0000

This report, an interim report covering the work completed on the CAL/APT Project during the period June 1994 through July 1995 presents the results of laboratory tests on the pavement materials, and evaluates a number of different pavement-materialscharacterization and pavement-performance-prediction procedures. This information as well as additional data to be acquired subsequently will be used for complete analyses of response of the first two pavement sections (four test sections) to accelerated loading with the Heavy Vehicle Simulator (HVS). Experience gained from test-section construction suggests that the following guidelines might be of use for the construction of highway pavements by Caltrans: Reduce the length of mix that can be laid down prior to beginning compaction, Increase the minimum compaction thickness, especially for placement over cold existing surfaces and during night construction, Require simultaneous construction of adjoining lanes where feasible and, Install...

Investigation of Design and Construction Issues for Long Life Concrete Pavement Strategies

Fri, 30 Oct 2020 00:00:00 +0000

The California Department of Transportation (Caltrans) Long-Life Pavement Rehabilitation Strategies (LLPRS) Task Force was commissioned in April 1997. The product that Caltrans has identified for the LLPRS Task Force to develop is Draft Long Life Pavement Rehabilitation guidelines and specifications for implementation on projects in the 1998/99 fiscal year. The focus of the LLPRS Task Force has been rigid pavement strategies. A separate task force has more recently been established for flexible pavement strategies, called the Asphalt Concrete Long-Life (AC Long-Life) Task Force. The University of California at Berkeley (UCB) and its subcontractors, Dynatest, Inc., the Roads and Transport Technology Division of the Council for Scientific and Industrial Research (CSIR), and Symplectic Engineering Corporation, Inc. are investigating for Caltrans the viability of various LLPRS optional strategies that have been proposed.

Fatigue Performance of Asphalt Concrete Mixes and Its Relationship to Asphalt Concrete Pavement Performance in California

Fri, 30 Oct 2020 00:00:00 +0000

In California, fatigue cracking is considered to be the most important type of distress affecting the performance of asphalt concrete pavements on major state highways. This report describes the results of a laboratory study of the fatigue response of a typical California asphalt concrete mix to define the effects of degree of compaction (as measured by air-void content), asphalt content, and aging on this performance parameter. The test results are then used in analytical simulations to estimate the effects of asphalt and air-void contents (with and without long-term-aging) on pavement performance. These simulations demonstrate that accurate construction control of air void content is more important than accurate control of asphalt content relative to the design target values. For example, a mixture targeted at 5-percent asphalt and 5-percent air voids will suffer a 30-percent reduction in fatigue life if the air-void content exceeds its target by 1-percent but only a 12- percent...

Analysis of Durability of Advanced Cementitious Materials for Rigid Pavement Construction in California

Fri, 30 Oct 2020 00:00:00 +0000

Caltrans specifications for the construction of rigid pavements require rapid setting, high early strength, superior workability concrete with a desired 30 year plus service life. These strict specifications provide the motivation for the investigation of advanced cementitious materials for pavement construction. The cementitious materials under consideration by Caltrans may be classified into four categories: Portland cements and blends, calcium aluminate cements and blends, calcium sulfoaluminate cements, and fly ash-based cements. To achieve the desired 30+ year design life, it is essential to select materials that are expected to exhibit long-term durability. Because most of the cementitious materials under consideration have not been extensively used for pavement construction in the United States, it is essential to characterize the long-term durability of each material. This report provides general information concerning the deleterious reactions that may damage concrete...

Contact Stresses of Pneumatic Tires Measured with the Vehicle-Road Surface Pressure Transducer Array (VRSPTA) System for the University of California at Berkeley (UCB) and the Nevada Automotive Test Center (NATC)

Fri, 30 Oct 2020 00:00:00 +0000

This report concentrates on the measurements of the three-dimensional (3-D) tire/pavement contact stress distributions for several pneumatic bias (or cross ply) and radial type tires used for Accelerated Pavement Testing (APT) at UCB and radial tires used by NATC at its Westrack test facility. The 3-D contact stress measurements were conducted with the Vehicle-Road Surface Pressure Transducer Array (VRSPTA) system. The VRSPTA system is in essence a “Stress-In-Motion” (SIM) system because it was developed to quantify the contact stresses between the tire and the pavement surface. As the VRSPTA system used for this study is the second prototype, it is referred to in this study as the “VRSPTA SIM Mark II” system. It was originally developed in South Africa for use in Accelerated Pavement Testing (APT) with the South African Heavy Vehicle Simulator (HVS).

CAL/APT Goal LLPRS--Rigid Phase III: Concrete Test Section 516CT Report

Fri, 30 Oct 2020 00:00:00 +0000

Over the past 50 years, only several full-scale concrete pavements have been tested, e.g., the AASHO Road Test, Mn/ROAD, and the various US Army Corps of Engineers tests (1). These full-scale test pavements have resulted in essential information for further improvement in pavement design procedures. They have also raised many questions that need to be answered with future road tests. The use of accelerated pavement testing equipment enables full-scale concrete pavements to be constructed and tested more cheaply than road tests. Caltrans currently owns two heavy vehicle simulators (HVS), which have been used to load asphalt concrete pavements at the University of California at Berkeley. The HVS allows for continuous load testing in a controlled environment and the potential for reduced variability in materials and testing. In order to evaluate the future performance of rehabilitated concrete pavements, the second HVS was used to test an accelerated Portland Cement Concrete pavement...

CAL/APT Program: Asphalt Treated Permeable Base (ATPB), Laboratory Tests, Performance Predictions and Evaluation of Caltrans and Other Agencies Experience

Fri, 30 Oct 2020 00:00:00 +0000

This report is one of a series detailing the results of the CAL/APT program, a research effort being performed jointly by the University of California, Berkeley Pavement Research Center and the California Department of Transportation (Caltrans). It contains an evaluation of the performance of asphalt treated permeable base (ATPB) in asphalt concrete pavements based on observation, laboratory testing of ATPB, and computer simulation of representative pavement structures. The evaluation includes: 1) a summary of Caltrans experience with ATPB and drainage systems relative to their development and implementation, together with observations of field performance with respect to maintainability and stripping of asphalt treated materials; 2) a summary of the characteristics and performance of ATPB materials and drainage systems used by two other highway agencies; 3) results of laboratory investigation of the stiffness and permanent deformation characteristics of ATPB mixes, including...

Warm-Mix Asphalt Study: Laboratory Test Results for AkzoNobel Rediset^TM WMX

Fri, 30 Oct 2020 00:00:00 +0000

This report describes a laboratory testing study that compared the performance of a control mix, produced and compacted at conventional hot-mix asphalt temperatures, with a mix containing Rediset^TM WMX warm-mix additive (referred to in this report as Rediset), produced and compacted at approximately 35°C (63°F) lower than the control. Key findings from the study include: No problems were noted with producing and compacting the Rediset mix at the lower temperatures in the laboratory. The air-void contents of individual specimens were similar for both mixes, indicating that satisfactory laboratory-mixed and compacted specimens can be prepared with the warm mix. Interviews with laboratory staff revealed that no problems were experienced with preparing specimens at the lower temperatures. Improved and safer working conditions at the lower temperatures were identified as an advantage. The laboratory test results indicate that use of the Rediset warm-mix asphalt...

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Aggregate Base (AB)--Section 501RF

Fri, 30 Oct 2020 00:00:00 +0000

This report is the third in a series which describe the results of tests on full-scale pavements constructed an the Richmond Field Station (RFS) which have been designed and constructed according to Caltrans procedures. It contains a summary of the results of their interpretation of the Heavy Vehicle Simulator (HVS) tests on the second of four pavements test sections, and asphalt-concrete sections containing an untreated aggregate base designated Section 501RF. The tests on the four test sections have been performed as part of Goal 1 of the CAL/APT Strategic Plan (1). One objective of the test program is to develop data to quantitatively verify existing Caltrans pavement design methodologies for asphalt treated permeable base (ATPB) pavements and conventional aggregate base pavements with regard to failure under trafficking at moderate temperatures (Goal 1), while preparing a uniform platform on which overlays (Goal 3 of the Strategic Plan) will be constructed which also will...

CAL/APT Program--Comparison of Caltrans and AASHTO Pavement Design Methods

Fri, 30 Oct 2020 00:00:00 +0000

This report compares the Caltrans and AASHTO pavement thickness design procedures. The design comparisons include pavement structures subjected to a range in traffic, as represented by Traffic Indexes of 7, 9, 11, 13, and 15, and a range in subgrade strengths, as measured by subgrade R-values of 5, 20, and 40. This report has four objectives: 1. Quantify the differences in pavement thickness resulting from use of the two methods. 2. Examine differences in predicted pavement performance for pavement designs considered equal within the Caltrans method. Related to this objective is the examination of the Gravel Factors for aggregate base and asphalt concrete. 3. Evaluate the effect of assumed drainage conditions on the pavement structures designed using the AASHTO method and relate this effect to the Caltrans method. 4. Demonstrate the flexibility of the mechanistic-empirical design procedure developed as part of the CAL/APT program to quantitatively, systematically, and rationally...

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Asphalt Treated Permeable Base (ATPB) Section 500RF

Fri, 30 Oct 2020 00:00:00 +0000

This report is the second in a series which describe the results of tests on full-scale pavements constructed at the Richmond Field Station (RFS) which have been designed and constructed according to Caltrans procedures. It contains a summary of the results and their interpretation of the Heavy Vehicle Simulator (HVS) tests on the first of four pavement test sections, an asphalt-concrete section containing an asphalt-treated permeable base (ATPB), designated section SOORF. The tests on the four test sections have been performed as part of Goal 1 of the CALIAPT Strategic Plan. Results of the test and their analysis indicate the following: (1) the HVS testing environment at the Richmond Field Station with respect to fatigue performance is more benign relative to moisture effects but provides a slightly more severe temperature environment than that which might be expected in natural California settings, (2) the importance of mix compaction on pavement performance has been conclusively...

Case Study of Urban Concrete Pavement Reconstruction and Traffic Management for the I-10 (Pomona, CA) Project

Wed, 28 Oct 2020 00:00:00 +0000

A case study was performed on a Caltrans concrete rehabilitation project near Los Angeles on Interstate 10. The project was unique in that the contractor had to remove and replace 2.8 lane-km of concrete pavement in a 55-hour weekend closure. The existing cement treated base was not removed except in places where it had deteriorated, and a fast setting hydraulic cement concrete with a 4-hour opening strength was used for the surface concrete. The contractor used a concurrent working method in which demolition and concrete paving occurred simultaneously and only a single lane was removed and replaced. The contractor had only one standard width construction access lane (3.7 m) and a shoulder width of less than 3.0 m. The contractor successfully completed this 2.8 lane-km objective in 55 hours and was eligible for a $500,000 bonus per the contract. The demolition operation took 76 percent longer than planned, but it did not delay the overall progress of the project. The concrete...

Constructability Analysis for Long Life Concrete Pavement Rehabilitation Strategies

Wed, 28 Oct 2020 00:00:00 +0000

One of the main objectives of the Caltrans Long Life Pavement Rehabilitation Strategies for rigid pavements (LLPRS-Rigid) is to have a construction productivity of approximately 6 lane-kilometers within a 55-hour construction window. This productivity objective must not conflict with the other two main LLPRS-Rigid objectives: to provide 30 plus years of pavement service life and to minimize pavement maintenance. This report describes the processes and results of a constructibility and productivity analysis for the Caltrans LLPRS-Rigid project, focusing on optimizing the maximum production capability within a 55-hour weekend closure. The analyses explored the effect of the following parameters on the concrete pavement construction productivity in California: pavement design profile, curing time, number and capacity of resources, number of lanes to pave, type of construction scheduling, and alternative lane closure tactics. The typical construction processes for concrete pavement...

Caltrans Accelerated Pavement Test (CAL/APT) Program Summary Report Six Year Period: 1994-2000

Wed, 28 Oct 2020 00:00:00 +0000

This report provides a summary of the Phase II portion (1994-2000) of the Caltrans Accelerated Pavement Testing (CAL/APT) Program. This research and development activity is a joint effort between Caltrans (California Department of Transportation), the University of California at Berkeley (UCB), the Division of Roads and Transport Technology of the Council of Scientific and Industrial Research (CSIR) of the Republic of South Africa, and Dynatest Consulting, Inc., of Ventura, California. The program utilizes two Heavy Vehicle Simulators (HVS) developed in South Africa. One of the HVS units is used to test full-scale pavements in a controlled environment at the UCB Pavement Research Center, located at the University of California Berkeley Richmond Field Station, while the other is utilized for testing in-service pavements and is currently in operation on State Route 14 near Palmdale, California. An extensive laboratory testing program involving the laboratories of both UCB and Caltrans...

Construction, Instrumentation, and Testing of Fast-Setting Hydraulic Cement Concrete in Palmdale, California

Wed, 28 Oct 2020 00:00:00 +0000

This report details the fast-setting hydraulic cement concrete (FSHCC) field construction. instrumentation, and strength testing of the field heavy vehicle simulator (HVS) test site on State Route 14 near Palmdale, California, which took place from June 5-18, 1998. This research was conducted as part of the California Accelerated Pavement Testing Program (CAL/APT) to look at the Caltrans proposed long-life pavement rehabilitation strategies (LLPRS). The project work included installation of internal (embedded in the pavement) and external pavement instrumentation, construction material sampling and testing, full-scale accelerated pavement testing on the field-constructed FSHCC pavements using Caltrans Heavy Vehicle Simulator No. 2 (HVS2), and monitoring of the loaded and unloaded test sections with respect to dynamic and environmental loading. The project work also included a laboratory component to validate the field HVS results, as well as computer modeling and analysis.

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Performance of Drained and Undrained Flexible Pavement Structures under Wet Conditions Test Data from Accelerated Pavement Test Section 544–Undrained

Wed, 28 Oct 2020 00:00:00 +0000

This report presents the data for the accelerated pavement testing (APT) program conducted using the Heavy Vehicle Simulator (HVS) on Section 544. This section is part of the accelerated test program described in the test plan for CAL/APT Goal 5, “Performance of Drained and Undrained Flexible Pavement Structures under Wet Conditions.”(1) Section 544 was tested to evaluate the performance of a typical California “undrained” pavement section under wet conditions and to compare its performance with that of Section 543 (a drained pavement section) in the same condition. From the Caltrans standpoint, an “undrained” pavement section is a conventional flexible pavement that does not have a permeable layer between the asphalt concrete and the aggregate base. A “drained” pavement section is a conventional flexible pavement that includes a 75-mm layer of asphalt treated permeable base (ATPB) between the asphalt concrete and aggregate base connected to a drainage system at the shoulder....

Accelerated Test Method for Measuring Sulfate Resistance of Hydraulic Cements for Caltrans LLPRS Program

Wed, 28 Oct 2020 00:00:00 +0000

Many California soils are rich in sulfates, which can have deleterious effects on the cements used in rigid pavements. Field experience has demonstrated that sulfate attack usually manifests itself in the form of loss of adhesion and strength. In order to assess the sulfate susceptibility of cements submitted to the Caltrans Long Life Pavement Rehabilitation Strategy (LLPRS) program, an accelerated test program was undertaken. In the accelerated test method employed, changes in cement paste strength after periods of sulfate exposure relative to the strength after seven days hydration served to indicate the sulfate resistance of the cement in question. Five cements submitted to Caltrans by four different manufacturers, and four portland cement mixes prepared in the laboratory were tested by an accelerated test method in which pH and sulfate concentration remained constant. Conditions provided in this accelerated test method are similar to field conditions, and results should...

UCPRC Life Cycle Assessment Methodology and Initial Case Studies for Energy Consumption and GHG Emissions for Pavement Preservation Treatments with Different Rolling Resistance

Mon, 26 Oct 2020 00:00:00 +0000

This report describes a pavement life cycle assessment (LCA) model developed to initially evaluate total energy use and greenhouse gas (GHG) emissions from pavement maintenance and rehabilitation (M&R) strategies. This LCA model allows analysis of the energy consumption and GHG emissions associated with material production, construction, and vehicle operation during pavement use, which includes the effects of pavement roughness and texture on vehicle operation; at this time the model does not include the effects of pavement deflection. Other types of treatments and the materials used for them, as well as other effects of the pavement on the environment in the pavement Use Phase will be considered in future studies. The model was used to evaluate four case studies of Caltrans pavement preservation treatments for both asphalt and concrete surfaces with different roughness and texture and traffic levels. The case studies were performed to provide a preliminary indication of the...

Superpave Implementation Phase II: Comparison of Performance-Related Test Results

Mon, 26 Oct 2020 00:00:00 +0000

Although Caltrans has utilized the Hveem mix design process for hot mix asphalt for decades, it is currently implementing the Superpave mix design procedure, and is interested in including performance-related tests for mix design and quality assurance. Performance-related tests are also used for Caltrans mechanistic-empirical (ME) pavement design. This report includes descriptions of current performance-related tests and alternatives, including tests using the Asphalt Mixture Performance Tester (AMPT) device for permanent deformation, stiffness and fatigue, and other alternatives to the flexural beam and repeated shear tests currently used for ME characterization by Caltrans. The tests are compared for mixture design and quality assurance, and for characterization for ME design in terms of the usefulness of the results, and the difficulty and time required to obtain results. The report also presents an evaluation of the effects on mix properties for Hveem versus Superpave mix...

Logistics Augmentation to the Freight-Truck-Pavement Interaction Pilot Study: Final Report

Mon, 26 Oct 2020 00:00:00 +0000

The objectives of this logistics augmentation to the Freight-Truck-Pavement interaction pilot study are: (1) to provide a basic understanding to Caltrans of private-sector decision making in road-freight transportation; (2) to identify and describe the comprehensive set of interactions between the efficiency and efficacy of road-freight transportation and the capacity, performance and regulation of road infrastructure in the state and recommend which of these interactions warrant more in-depth assessment on a statewide scale to quantify the overall economic and efficiency impact road infrastructure decisions have on the economy of California; and (3) to illustrate the value of direct interactions and consultations with private companies in exploring private sector decision making and the interdependence of these decisions on public sector actions. Conclusions: By using desktop studies, qualitative analysis, and case studies, this study has shown that road infrastructure and regulation,...

Development of Recommended Guidelines for Preservation Treatments for Bicycle Routes

Mon, 26 Oct 2020 00:00:00 +0000

This project was a continuation of a previous study that focused on the effects of pavement macrotexture on bicycle ride quality using input from bicycle club members and their bicycles on state highways, and considered changes to Caltrans chip seal specifications that resulted in seals with larger maximum size stones being typically used. This second project included a wider range of bicycle riders and bicycle types, considered pavement roughness and distresses in addition to macrotexture, and included measurements on urban preservation treatments and city streets as well as on treatments on state highways and county roads. This study also examined preservation treatment aggregate gradations and the mechanistic responses of bicycles to pavement macrotexture and roughness. The results of both projects were used to prepare recommended guidelines for the selection of preservation treatments that are best suited to bicycle routes on California’s state highways and local streets....

Investigation of the Effect of Reclaimed Asphalt Pavement and Reclaimed Asphalt Shingles on the Performance Properties of Asphalt Binders: Phase 1 Laboratory Testing

Mon, 26 Oct 2020 00:00:00 +0000

Including some reclaimed asphalt in new asphalt concrete mixes used on pavements has attracted considerable interest from departments of transportation and other agencies mainly because of the cost savings and environmental benefits associated with substituting reclaimed binder for some virgin binder. However, the laboratory testing in this study, which was all undertaken on unaged asphalt specimens, has clearly shown that although adding reclaimed asphalt to new mixes is likely to increase mix stiffness, which in most instances is likely to improve its rutting resistance, the cracking resistance properties could be diminished. Preliminary findings from this study indicate that: The asphalt binder in reclaimed asphalt shingles (RAS) may not effectively mobilize and blend with virgin asphalt. If used as a binder replacement, this recycled asphalt could reduce the actual effective binder content in the mix, which could in turn lead to early cracking and raveling. The results of...

Implementation of New Quieter Pavement Research: Accelerated Pavement Testing and Laboratory Evaluation of Different Open-Graded Hot-Mix Asphalt Materials

Mon, 26 Oct 2020 00:00:00 +0000

This study presented in this report is part of a long-term effort that started in 2005 to develop the specifications, guidelines, standardized laboratory and field test methods, and other information needed for quieter pavement research to be incorporated into standard Caltrans practices, and lead to quieter pavements. Based on an earlier laboratory study, several open-graded friction course (OGFC) mixes were selected for further evaluation with accelerated pavement testing using the Heavy Vehicle Simulator (HVS) and laboratory testing on plant-produced materials. These selected mixes had shown good overall laboratory performance in terms of durability and sound absorption, which is correlated with tire/pavement noise. Specifically, the following HVS test cells were constructed for this experiment: Cell A: Caltrans 3/8 inch mix with PG 76-22PM binder, average as-built thickness = 0.06 ft. Cell B1: #4P mix with PG 76-22PM binder, average as-built thickness = 0.06 ft. Cell B2: Same...

The Design and Implementation of the Pavement Research Center Heavy Vehicle Simulator Database

Fri, 23 Oct 2020 00:00:00 +0000

This document covers the design, implementation and usage of the heavy vehicle simulator (HVS) database in use by the Pavement Research Center (PRC) at the University of California (UC), which is referred to as the PRC-HVS database. This report describes the portion of the database used to store all of the data collected directly from HVS test sections. The same database is used to store data from both flexible and rigid pavement sections. Not included in this report are discussions of the environmental data, long term pavement performance data, and laboratory testing data, which are also included in the PRC database and which have been collected since 1995 during the operation of the two Caltrans heavy vehicle simulators. This report is broken into three main sections. The first provides some background about the HVS activities and the reasons for various choices in the database design. The second covers the design of the database. The final section covers the processing of the...

Calibration of CalME models using WesTrack Performance Data

Fri, 23 Oct 2020 00:00:00 +0000

Since 2000 the UCPRC has been developing a mechanistic-empirical (M-E) pavement design method for Caltrans. The software associated with the flexible pavement design methodology is termed CalME. This report presents the results of a validation and calibration study for the CalME software using the performance data from the FHWA’s WesTrack accelerated pavement test (APT) program. This APT was conducted in the period between March 1996 and February 1999 at a site near Carson City, Nevada; all 26 initial test sections were used in the study. These sections, constructed with Superpave-type hot-mix asphalt (HMA) consisting of a single source for the aggregate and asphalt binder (PG64-28), were subjected up to approximately 5 million ESALs. HMA variables included: aggregate gradation, asphalt content, and degree of compaction. The calibration procedure used both falling weight deflectometer (FWD) field test data and laboratory-measured properties of all the mixes. Laboratory-measured...

Investigation of Noise and Durability Performance Trends for Asphaltic Pavement Surface Types: Four-Year Results

Fri, 23 Oct 2020 00:00:00 +0000

The work presented in this report is a summary of a series of research projects, whose central purpose is to support the Caltrans Quieter Pavement Research Program, which has as its goals and objectives the identification of quieter, smoother, safer, and more durable pavement surfaces. The research has been carried out as Partnered Pavement Research Center Strategic Plan Elements (PPRC SPEs) 4.16, 4.19, and 4.27. In the study documented in this report, field data regarding tire/pavement noise, surface condition, ride quality, and macrotexture were collected over four consecutive years from pavements in California placed with open-graded and other asphaltic mixes. The four-year data were analyzed to evaluate the durability and effectiveness of open-graded mixes in reducing noise compared to other asphalt surfaces, including dense- and gap-graded mixes, and to evaluate the pavement characteristics that affect tire/pavement noise. The analysis in this report is a supplement and update...

Simulation of Cumulative Annual Impact of Pavement Structural Response on Vehicle Fuel Economy for California Test Sections

Fri, 23 Oct 2020 00:00:00 +0000

This report presents the preliminary results of a study of the effects of pavement structural response on excess fuel consumption (EFCS), which is defined as the additional fuel required to propel a vehicle on an “imperfect” pavement compared to the amount required on an “ideal” pavement. The study compared EFCS for a set of asphalt-surfaced test sections with a pavement with no structural response as well as with the effects of roughness and macrotexture on EFC. EFCS was calculated using three different models for a factorial that included seventeen asphalt-surfaced pavement field sections on the California state highway network with different structure types that were characterized by their viscoelastic properties. The results of the modeling were used to simulate annual EFCS for a factorial of vehicles, traffic flows, speed distributions, and climate regions typical of California. The sensitivity of EFCS to the variables in the factorial was analyzed, and the effects of structural...

Improved Methodology for Mix Design of Open-Graded Friction Courses

Fri, 23 Oct 2020 00:00:00 +0000

This study presents an improved methodology for the mix designs of open-graded friction courses (OGFC). The methodology has been enhanced by the development of an Excel macro in order to suggest revisions to California Test 368, Standard Method for Determining Optimum Binder Content (OBC) for Open-Graded Asphalt Concrete. In addition to the development of the Excel macro, one of the primary objectives of this study was to evaluate the effect that fines content has on mix performance, which cannot be identified by the “break point sieve” concept or by volumetric properties. The proposed OGFC mix design includes two phases: Phase I: Volumetric OGFC Mix Design and Phase II: Performance Testing. The tasks required to perform Phase I include the determination of material volumetric properties such as specific gravities, voids in coarse aggregate in dry-rodded condition (VCADRC), and asphalt absorption. These must be performed so it becomes possible to select three trial binder contents...

Surface Treatment Macrotexture and Bicycle Ride Quality

Fri, 23 Oct 2020 00:00:00 +0000

This memorandum summarizes the results of measurements of macrotexture on a set of Caltrans and local government pavement surface treatments, and the results of bicycle vibration measurements and a survey of bicycle ride quality on most of those sections. The work was performed to address concerns raised by local bicyclists regarding ride quality after a modified-binder seal coat (chip seal) was placed on State Route 1 in San Luis Obispo County (SLO-1). The test sections that were used for the bicycle vibration and ride quality measurements included various surface treatments on existing chip seals on State Route 198 in Monterey County (Mon-198), several locations on SLO-1, and on other state highway and county road sections in Yolo, Butte, El Dorado, Placer, Sonoma, Marin, and San Mateo counties. Macrotexture was measured in terms of mean profile depth (MPD). Three different test methods were used to measure MPD: the sand patch method and the laser texture scanner (LTS), which...

Development of Thin HMA Overlay Crack Initiation and Progression Probabilistic Models

Fri, 23 Oct 2020 00:00:00 +0000

This report presents the results of a study to evaluate fatigue cracking performance models for hot-mix asphalt (HMA) overlays placed on existing HMA pavements. Previously, data from the Washington State Department of Transportation (WSDOT) pavement management system (PMS) were used to develop separate models for crack initiation and progression. Later, these two models were combined into a combined model for the entire cracking process. The study presented in this report evaluates the combined model using the limited California PMS data available. This was done to assess the model’s ability to predict the performance of HMA overlays of cracked asphalt pavement in California. An earlier study identified that data in the WSDOT PMS primarily reflects the performance of overlays of 0.15 ft (45 mm) on pavement with low levels of existing cracking. However, a sensitivity analysis performed in this study indicates that the performance trends for California overlays predicted by the...

Laboratory Evaluation of the Noise and Durability Properties of Asphalt Surface Mixes

Fri, 23 Oct 2020 00:00:00 +0000

This study made comparisons of the expected noise and durability performance of asphalt surface mixes based on laboratory testing only, and recommended a set of surface mixes for field test sections with improved surface performance properties. The study included a series of experiments to investigate the effects of several important mix variables identified in studies of field test sections, including nominal maximum aggregate size, aggregate gradation, binder type, additive, air-void content, and aggregate shape, on mix properties related to pavement surface performance. The study also included several other mix designs that had good or promising performance histories, and compared them with current Caltrans mixes in terms of laboratory test results. Specimens were prepared and tested in the laboratory. The performance indicators evaluated in the laboratory included durability, permeability, sound absorption, and friction. Durability included raveling, moisture damage, reflective...

Warm-Mix Asphalt Study: Evaluation of Rubberized Hot- and Warm-Mix Asphalt with Respect to Emissions

Fri, 23 Oct 2020 00:00:00 +0000

In recent years, warm mix asphalt (WMA) technologies have been used to modify asphalt binders, with the aims of decreasing production and construction temperatures, reducing fumes and emissions, retaining the properties of the mix during long haul distances, and improving workability. Reduced production temperatures at the plant and during paving and compaction are believed to reduce emissions from the asphalt. The objective of this research study was to quantify the potential environmental benefits during paving operations with respect to the reduction of volatile and semi-volatile organic compounds and polycyclic aromatic hydrocarbons to confirm or refute this hypothesis. Asphalt plant stack emissions were not assessed as part of this study. A portable “flux” chamber was designed and fabricated to capture and directly measure emissions during paving operations. An analytical method was developed to identify and quantify alkane emissions using gas chromatography mass spectrometry...

Investigation of Noise, Ride Quality and Macrotexture Trends for Asphalt Pavement Surfaces: Summary of Six Years of Measurements

Fri, 23 Oct 2020 00:00:00 +0000

The work presented in this report is the culmination of a series of research projects, whose purpose is to support the Caltrans Quieter Pavement Research program. The goal of this program is to identify quieter, smoother, safer, and more durable pavement surfaces. The research has been carried out as Partnered Pavement Research Center Strategic Plan Element numbers 4.16, 4.19, 4.27, 4.29, and 4.39. This report presents six years of collected tire/pavement noise, ride quality, macrotexture, and other field data gathered on California pavements surfaced with four typical Caltrans asphalt mixes. The report also includes data from several pavement sections with experimental mixes and/or the results of side-by-side comparisons of different mixes. The experiment included pavements that ranged in age from newly paved (just after construction) to eight years old at the start of the study, resulting in data covering pavement surfaces with ages up to 15 years old. The six years of collected...

Results from Visual Inspection and Laboratory Testing for ASR in Existing Concrete Cores from Bridges and Pavements in California

Fri, 23 Oct 2020 00:00:00 +0000

The overall goal of this project was to evaluate with available cores the presence of alkali-silica reaction (ASR) in California bridges and pavements, to develop procedures for evaluation of ASR by Caltrans staff, and, potentially, to investigate several locations suspected of having ASR damage. This report summarizes the creation of an inventory for cores taken from bridges and pavements in previous projects, the results of visual inspection and strength testing to identify the potential presence of ASR, and the development of a draft approach for Caltrans staff to evaluate the potential for ASR in bridges and pavements. A spreadsheet database was prepared for storing inventory data for 265 pavement cores with four inch (100 mm) diameter and 311 bridge cores with two inch (50 mm) diameter. Most of the bridge cores were from the San Francisco Bay Area, while the pavement cores were collected from across the state. Visual inspection was performed on 259 of the pavement cores (including...

Mechanistic-Empirical (ME) Design: Mix Design Guidance for Use with Asphalt Concrete Performance-Related Specifications

Fri, 23 Oct 2020 00:00:00 +0000

Caltrans has adopted mechanistic-empirical (ME) methods for flexible pavement design, and is using performance-related construction specifications on some projects for hot mix asphalt. Performance-related specifications are used to help ensure that as-built materials meet the performance requirements assumed in ME pavement structural designs. PRS pose new challenges for materials producers and contractors who have never had to relate volumetric mix design parameters to achievement of mechanistic parameters for fatigue life and rutting resistance based on results from performance-related laboratory tests. The objective of this project is to provide guidance to mix designers and contractors to support their decision making regarding changes to mix designs to achieve PRS requirements. The guidance presented in this report was initially developed based on past experience. To validate the guidance and demonstrate its usage, a production mix approved by the California Department of...

Investigation of Tire/Pavement Noise for Concrete Pavement Surfaces: Summary of Four Years of Measurements

Thu, 22 Oct 2020 00:00:00 +0000

The objectives of the four-year quieter concrete pavement research study presented in this report were to measure noise from tire/pavement interaction, pavement smoothness, and drainability characteristics of concrete pavement surface textures currently used on the California state highway network. This study also was undertaken to develop recommendations for safe, durable, and cost-effective concrete pavement surface textures that minimize noise from tire/pavement interaction. The fourth and final year of this research study included testing on 60 test sections grouped by texture type as follows: 27 diamond ground (DG), 12 diamond grooved (Gr), 19 longitudinally tined (LT), 1 burlap drag (BD), and 1 longitudinally broomed (LB). Five of the 60 test sections were continuously reinforced concrete pavement (CRCP) and the rest were jointed plain concrete pavement (JPCP). This report presents the results of measurements of tire/pavement interaction noise and of the pavement smoothness...

Warm-Mix Asphalt Study: Evaluation of Hot and Warm Mix Asphalt with Respect to Binder Aging

Thu, 22 Oct 2020 00:00:00 +0000

Warm-mix asphalt (WMA) technologies are added to asphalt binders to lower production and construction temperatures, reduce emissions, allow for increase haul distances, and improve the workability. Reduced temperatures at the plant and during laydown and compaction are hypothesized to impact long-term oxidative aging behavior. This study attempted to quantify these impacts through characterization of field-aged unmodified and rubber-modified binders extracted and recovered from cores sampled from 13 test sections representing seven different WMA technologies and associated hot-mix controls. A dynamic shear rheometer (DSR) was used to evaluate the binder rheological properties at high temperatures with respect to expected rutting performance. The cup-and-bob DSR testing procedure was assessed as an alternative approach for testing rubberized binders. A bending beam rheometer (BBR) was used to characterize low-temperature properties. Test results did not appear to be influenced...

Network-Level Life-Cycle Energy Consumption and Greenhouse Gas from CAPM Treatments

Thu, 22 Oct 2020 00:00:00 +0000

This report describes a life-cycle assessment (LCA) approach developed to evaluate the energy consumption and greenhouse gas (GHG) reductions from the use of pavement maintenance treatments that improve smoothness on the California State Highway Network, as well as the cost-effectiveness of this approach. This analysis developed optimal roughness values to trigger maintenance and rehabilitation treatments to minimize life-cycle GHG emissions (measured in equivalent CO2 emissions [CO2-e]) as a function of the traffic volume of each pavement segment in the network. A set of pavement characteristics were used to describe each segment of the network and to evaluate the impact of pavement-induced rolling resistance under different pavement and traffic conditions. With the optimal trigger values, annualized reductions on the California State Highway Network over a ten-year analysis period were calculated to be 0.82, 0.57, and 1.38 million metric tons compared with results using historical...

Full-Depth Recycling Study: Test Track Construction and First-Level Analysis of Phase 1 and Phase 2 HVS Testing, Forensic Investigation, and Phase 1 Laboratory Testing

Thu, 22 Oct 2020 00:00:00 +0000

This first-level report describes the first two phases of a study comparing the performance of four different full-depth pavement reclamation strategies, namely pulverization with no stabilization (FDR-NS), stabilization with foamed asphalt and portland cement (FDR-FA), stabilization with portland cement only (FDR-PC), and stabilization with engineered asphalt emulsion (FDR-EE). A literature review, the test track layout and design, stabilization and asphalt concrete mix designs, and test track construction are discussed, as well as the results of Heavy Vehicle Simulator (HVS) and preliminary laboratory testing, and a forensic investigation of the HVS test sections. A number of problems were experienced during construction of the FDR-PC and FDR-EE lanes on the test track and consequently only the FDR-NS and FDR-FA lanes and one section of the FDR-PC lane (5 percent measured cement content) were considered satisfactorily uniform for the purposes of HVS testing. The FDR-FA and FDR-PC...

Performance-Based Pay Factors for Asphalt Concrete Construction: Comparison with a Currently Used Experience-Based Approach

Thu, 22 Oct 2020 00:00:00 +0000

Document summarizes a procedure to establish pay factors for asphalt concrete pavement construction using performance models for fatigue and rutting based on the analysis of accelerated pavement tests from the Caltrans Heavy Vehicle Simulator (HVS) and the WesTrack accelerated pavement performance test program. Results of the performance-based approach are compared with pay factors determined by the current Caltrans procedure using percent defective and experience-based weighting factors.

Vision for Caltrans/UC-Berkeley Partnered Pavement Research Center

Thu, 22 Oct 2020 00:00:00 +0000

The vision for the Caltrans/UCB Partnered Pavement Research Center is that Caltrans and other partners will have continuously improving state-of-the-art pavement technology to maximize the level of service to the users of Caltrans pavements, while optimizing expenditures on the pavement infrastructure.

Evaluation of Grind and Groove (Next Generation Concrete Surface) Pilot Projects in California

Thu, 22 Oct 2020 00:00:00 +0000

This research report presents the results of tire/pavement noise, friction, drainability, and profile measurements performed on conventional diamond grind (CDG) and grind and groove (GnG) concrete pavement surface textures as a part of the California Department of Transportation (Caltrans) Quieter Pavement Research (QPR) study to investigate tire/pavement noise on concrete pavements. The On-board Sound Intensity (OBSI) method (AASHTO TP 76) was used to measure tire/pavement noise. Longitudinal profile data were collected at the same time as the OBSI data using an inertial profiler (ASTM E950) and were used to calculate the International Roughness Index (IRI). Friction was measured using the Towed Skid Trailer (ASTM E274) and the California Portable Skid Tester (CT 342), and estimated using the Circular Track Meter (ASTM E2157) and Dynamic Friction Tester (ASTM E1911). Drainability was measured using the Outflow Meter (ASTM E2380). Seven pilot projects scheduled for CDG were selected...

Recent itsdavis_ucprc_researchreports items

Investigation into the Use of Reclaimed Asphalt Pavement in Gap- and Open-Graded Asphalt Rubber Mixes: Phase 2: Laboratory Testing of Aggregate Replacement and CalME Simulation

Evaluation of Sustainable and Cost-Effective Concrete Pavement Life

Cold Central Plant Recycling Study: Preliminary Determination of Maximum Time That Processed Material Can Be Stockpiled and Compacted

Update of the PG Binder Map in California Using the Enhanced Integrated Climate Model (EICM) and LTPPBind Online

Feasibility of Cold Central Plant Recycling Asphalt Mixtures for Airports: Task 1 Report

Cold Recycling Study: Testing to Develop Standard Mix Design and Quality Control/Quality Assurance Testing Procedures for Cold Recycling Project Specifications (Metric Units)

Cold Recycling Study: Testing to Develop Standard Mix Design and QualityControl/Quality Assurance Testing Procedures for Cold Recycling Project Specifications (Imperial Units)

Cold Central Plant Recycling Study: First-Level Analysis of Heavy Vehicle Simulator Testing

100% RAP Pilot Project on SBD 40: Material Testing, Life Cycle Assessment, Observations, and Findings

Final Noise and Smoothness Monitoring on Concrete Pilot Projects of Grind and Groove and Continuously Reinforced Concrete Pavements

Analysis of 30 Years of Pavement Temperatures using the Enhanced Integrated Climate Model (EICM)

Climate Regions for Mechanistic-Empirical Pavement Design in California and Expected Effects on Performance

Goal 4 Long Life Pavement Rehabilitation Strategies—Rigid: Laboratory Strength, Shrinkage, and Thermal Expansion of Hydraulic Cement Concrete Mixes

Performance of Drained and Undrained Flexible Pavement Structures in Accelerated Loading Under Wet Conditions–Summary Report Goal 5 Partnered Pavement Performance Program

Stiffness, Strength, and Performance of Unbound Aggregate Material: Application of South African HVS and Laboratory Results to California Flexible Pavements

Accelerated Laboratory Testing for Alkali-Silica Reaction Using ASTM 1293 and Comparison with ASTM 1260

Performance of Drained and Undrained Flexible Pavement Structures Under Wet Conditions – Accelerated Test Data, Test Section 545–Undrained

CAL/APT Program – Construction of the Goal 3 Overlays and Recommendations for Improved Overlay Performance in California

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Asphalt Treated Permeable Base (ATPB)–Section 502CT

Analysis of Sensitivity of Plain Jointed Concrete Pavement in California to Early-Age Cracking Using HIPERPAV

Normalizing the Behavior of Unsaturated Granular Pavement Materials

Assessing the Economic Benefits from the Implementation of New Pavement Construction Methods

Analysis and Estimation of Effective Built-In Temperature Difference for North Tangent Slabs: Data Analysis from the Palmdale, California Rigid Pavement Test Site

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Untreated Aggregate Base–Section 503RF

Shrinkage and Thermal Cracking of Fast Setting Hydraulic Cement Concrete Pavements in Palmdale,California

Accelerated Laboratory Testing for High Early StrengthConcrete for Alkali Aggregate Reaction

Evaluation of the Maturity Method for Flexural Strength Estimation in Concrete Pavement

Palmdale South Tangent Slab Built-In Curling and Cracking: Preliminary Analysis Report

Rutting of Caltrans Asphalt Concrete and Asphalt-Rubber Hot MixUnder Different Wheels, Tires and Temperatures – AcceleratedPavement Testing Evaluation

HVS Test Results on Fast-Setting Hydraulic Cement Concrete, Palmdale, California Test Sections, South Tangent

Performance of Caltrans Asphalt Concrete and Asphalt-Rubber Hot Mix Overlays at Moderate Temperatures—Accelerated Pavement Testing Evaluation

Data Mining of the Caltrans Pavement Management System (PMS) Database

Constructability and Productivity Analysis for Long Life Asphalt Concrete Pavement Rehabilitation Strategies

Life Cycle Assessment of Asphalt Binder, Warm Mix Asphalt Additives, and Bonded Concrete Overlay of Asphalt for California Conditions

Impact of Silo Storage on the Performance of Plant-Produced Mixes Containing High Content of Reclaimed Asphalt Pavement or Reclaimed Asphalt Shingles

Pavement ME JPCP Transverse Cracking Model Calibration and Design Catalog Framework (Version 2.5.5)

Development of Performance-Based Specifications for Asphalt Rubber Binder: Phase 2g Testing of Plant-Sampled Binders and RHMA-G Mixes

Analysis of Recycling Agent Effects on the Mechanical Properties of HMA with High Recycled Binder Ratios

Pavement Recycling: Shrinkage Crack Mitigation in Cement-Treated Pavement Layers—Phase 2b Laboratory Testing and Performance Modeling

Drying Shrinkage Response of Full-Scale Thin Concrete Overlay on Asphalt Sections

Preliminary Study on Developing a Surrogate Performance-Related Test for Fatigue Cracking of Asphalt Pavements

Development of Performance-Based Specifications for Asphalt Rubber Binder: Interim Report on Phase 1 and Phase 2 Testing

First-Level Analysis of Phase 1 Heavy Vehicle Simulator and Laboratory Testing on Four RHMA-G Mixes to Investigate Nominal Maximum Aggregate Size, Layer Thickness, and Performance with Aggregate Replacement from Reclaimed Asphalt Pavement

Development of Performance-Based Specifications for Asphalt Rubber Binder: Phase 2g Additional Testing of Five Plant-Sampled Binders and RHMA G Mixes

Water Quality and Toxicity Evaluation of Discharge Generated from Asphalt Pavement Surfacing Materials

Pavement Recycling: Shrinkage Crack Mitigation in Cement-Treated Pavement Layers — Phase 2a Literature Review and FDR-C Test Road Construction and Monitoring

Investigation of the Effect of Pavement Deflection on Vehicle Fuel Consumption: Field Testing and Empirical Analysis

Pavement ME Sensitivity Analysis (Version 2.5.3)

Concrete Overlay on Asphalt Pilot Project at Woodland SR 113: Construction

Increasing Crumb Rubber Usage by Adding Small Amounts of Crumb Rubber Modifier in Hot-Mix Asphalt. Phase 1: Laboratory Tests and CalME Simulations

Pavement ME Evaluation of the NCHRP 1-61 Thin Concrete Overlay on Asphalt Sections

eLCAP: A Web Application for Environmental Life Cycle Assessment for Pavements

Optimizing Rubberized Open-graded Friction Course (RHMA-O) Mix Designs for Water Quality Benefits: Phase I: Literature Review

Updates to CalME and Calibration of Cracking Models

Evaluation of Modified Binder Gap-Graded Mixes for Half-Thickness Reflective Cracking Overlays

Pay Factors for Asphalt-Concrete Construction: Effect of Construction Quality on Agency Costs

Preliminary Evaluation of Proposed LLPRS Rigid Pavement Structures and Design Inputs

Effects of Material Properties, Specimen Geometry, and Specimen Preparation Variables on Asphalt Concrete Tests for Rutting

Initial CAL/APT Program: Site Information, Test Pavement Construction, Pavement Materials Characterizations, Initial CAL/APT Test Results, and Performance Estimates

Investigation of Design and Construction Issues for Long Life Concrete Pavement Strategies

Fatigue Performance of Asphalt Concrete Mixes and Its Relationship to Asphalt Concrete Pavement Performance in California

Analysis of Durability of Advanced Cementitious Materials for Rigid Pavement Construction in California

Contact Stresses of Pneumatic Tires Measured with the Vehicle-Road Surface Pressure Transducer Array (VRSPTA) System for the University of California at Berkeley (UCB) and the Nevada Automotive Test Center (NATC)

CAL/APT Goal LLPRS--Rigid Phase III: Concrete Test Section 516CT Report

CAL/APT Program: Asphalt Treated Permeable Base (ATPB), Laboratory Tests, Performance Predictions and Evaluation of Caltrans and Other Agencies Experience

Warm-Mix Asphalt Study: Laboratory Test Results for AkzoNobel RedisetTM WMX

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Aggregate Base (AB)--Section 501RF

CAL/APT Program--Comparison of Caltrans and AASHTO Pavement Design Methods

CAL/APT Program: Test Results from Accelerated Pavement Test on Pavement Structure Containing Asphalt Treated Permeable Base (ATPB) Section 500RF

Case Study of Urban Concrete Pavement Reconstruction and Traffic Management for the I-10 (Pomona, CA) Project

Constructability Analysis for Long Life Concrete Pavement Rehabilitation Strategies

Caltrans Accelerated Pavement Test (CAL/APT) Program Summary Report Six Year Period: 1994-2000

Construction, Instrumentation, and Testing of Fast-Setting Hydraulic Cement Concrete in Palmdale, California

Performance of Drained and Undrained Flexible Pavement Structures under Wet Conditions Test Data from Accelerated Pavement Test Section 544–Undrained

Accelerated Test Method for Measuring Sulfate Resistance of Hydraulic Cements for Caltrans LLPRS Program

UCPRC Life Cycle Assessment Methodology and Initial Case Studies for Energy Consumption and GHG Emissions for Pavement Preservation Treatments with Different Rolling Resistance

Superpave Implementation Phase II: Comparison of Performance-Related Test Results

Logistics Augmentation to the Freight-Truck-Pavement Interaction Pilot Study: Final Report

Development of Recommended Guidelines for Preservation Treatments for Bicycle Routes

Warm-Mix Asphalt Study: Laboratory Test Results for AkzoNobel Rediset^TM WMX