Evaluation of Moisture Damage in Hot-Mix Asphalt Using Simple Peformance and Superpave Indirect Tension Tests

Moisture damage has been one of the major concerns for hot mix asphalt (HMA) pavements. In the present study, efforts have been made to evaluate the moisture damage of a dense-graded surface HMA mixture using simple performance test (SPT) and SuperpaveTM indirect tension test (IDT). Coarse gravels at three different angularity levels (100, 50 and 0 percent fractured surface counts) were used to produce mixtures with similar aggregate gradations. Asphalt binders (PG 64-22) with and without amine-based antistrip additive (ASA) were used to make mixtures for laboratory moisture damage evaluations. Specimens were conditioned by four different methods: 1) one cycle of freeze-thaw (F-T), 2) two cycles of F-T, 3) 500 cycles of pore pressure pulses with Moisture Induced Stress Tester (MIST), and 4) 1000 cycles with MIST. The dynamic modulus, Superpave IDT creep, resilient modulus and strength tests were performed on conditioned and unconditioned specimens. The results from this study indicated that the SPT Dynamic Modulus Test and the Superpave IDT with F-T or MIST conditionings were effective to characterize lab-measured moisture susceptibility of HMA mixtures. Increase F-T or MIST cycles would increase moisture damage in HMA mixture. Amine-based antistrip additive was effective to decrease the moisture damage in HMA mixtures. Increase coarse aggregate angularity (CAA) levels could increase dynamic modulus; however, it seemed that CAA had not significant effects on the lab-measured moisture resistance of HMA mixtures.