Laboratory Evaluation of Untreated and Treated Pavement Base Materials

Abstract

Pavement performance is related to resilient modulus and permanent deformation properties of pavement materials, as well as other factors such as environmental and traffic conditions. Current resilient modulus test procedures and correlations do not fully describe permanent deformation properties. This limitation signifies the need for a permanent deformation test procedure for proper material characterization. The objective of this study was to evaluate resilient and permanent deformation properties of seven base materials with a proposed permanent deformation test that can provide both resilient modulus and permanent deformation properties. The base materials used were obtained from test sections recently constructed at the Louisiana Pavement Research Facility. These included crushed limestone, blended calcium sulfate, blended calcium sulfate treated with slag, blended calcium sulfate treated with fly ash, recycled asphalt pavement, foamed asphalt–treated 100% recycled asphalt pavement, and foamed asphalt–treated blend of 50% recycled asphalt pavement and 50% soil cement. Laboratory repeated load triaxial permanent deformation and material property tests were performed on these materials. A power model that correlated the accumulated permanent strain to the number of repeated load cycles for each material considered was developed. A good correlation between resilient moduli and permanent strains was observed. Blended calcium sulfate treated with slag exhibited the highest resilient modulus and the lowest permanent deformation values of the investigated materials, followed by blended calcium sulfate treated with fly ash, blended calcium sulfate, crushed limestone, and recycled asphalt pavement.