University of California Pavement Research Center

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 be indicative of field performance.