Effects of Additional Antistrip Additives on Durability and Moisture Susceptibility of Granite-Based Open-Graded Friction Course

Abstract

This study aimed to evaluate the effects of additional antistrip additives on the durability and moisture susceptibility of granite-based open-graded friction course, referred to as FC-5 asphalt mixture. The laboratory testing involved two granite-based FC-5 mixtures containing 1% hydrated lime (by weight of aggregate), 1% hydrated lime plus 0.5% liquid antistrip (LAS) additive (by weight of asphalt binder), 1.5% hydrated lime, and 1.5% hydrated lime plus 0.5% LAS additive. Two sources of granite aggregates were obtained, one from Junction City, Georgia, and the other from a regional supplier with an original source from Nova Scotia, Canada. Four types of LAS additives were collected for this study. A binder bond strength test was used to select the LAS agents that provided the best improvement in moisture resistance. The FC-5 mixtures were fabricated in the laboratory using two FC-5 mix designs provided by the Florida DOT. The specimens were conditioned by the asphalt pavement weathering system to simulate long-term aging and moisture conditioning in the field. Mixture performance tests, including the Cantabro test, tensile strength ratio test, and Hamburg wheel tracking test, were used to evaluate the durability and moisture susceptibility of FC-5 mixtures. Finally, a cost-benefit analysis was performed to determine the cost-effectiveness of the FC-5 mixtures with antistrip additives. This study found that the addition of LAS additive, an extra 0.5% hydrated lime, or both produced longer lasting FC-5 mixtures, and the additional antistrip additives would improve the cost-effectiveness of FC-5 mixtures.