Resilient moduli responses of polymeric-treated pavement foundation materials under repeated loading

Polyacrylamide (PAM) has been shown to enhance strength, stiffness and durability characteristics of granular materials, in addition to providing lower carbon footprints when compared to traditional stabilisers. In this study, the responses of granular subbase materials for flexible pavements, under simulated traffic loading, have been investigated using repeat load triaxial (RLT) testing. Three types of granular materials treated with PAM have been tested to assess changes in engineering performance and responses to simulated traffic. Untreated materials were also tested for comparison. The engineering performance of these materials (treated and untreated) in terms of strength and stiffness were assessed by conducting unconfined compressive strength (UCS) and RLT tests. Results indicate that samples treated with PAM yield higher UCS and resilient modulus values than the untreated samples, with the magnitude of the resilient modulus being dependent on compaction effort. Data related to response under simulated loads has also been collected and used to calibrate an existing model to predict resilient modulus response for each soil type from its physical and engineering properties. The calibrated models were found to satisfactorily simulate the resilient modulus response of the RLT experimental test data.