Abstract:
Depending on the local conditions and structural design of the pavement, multiple asphalt concrete layers including base, intermediate, and wearing courses are used. Typically, the base and intermediate layers have larger aggregate sizes and lower total asphalt binder contents as compared with the wearing course. Recently, cold recycled (CR) asphalt mixtures have gained attention as an alternative to the typical base, and to some extent intermediate courses, because of economic and environmental advantages. Challenges with CR include the potential high variability of recycled asphalt pavement (RAP) and lack of knowledge in relation to structural contribution and long-term performance of such layers. This study investigates four different types of CR and four hot mixed plant-produced asphalt mixtures (three intermediate courses and one base course) that are typical mixtures used in New Hampshire. The laboratory performance evaluation is conducted through the resilient modulus (Mr), complex modulus (E*), semi-circular bend and direct tension cyclic fatigue (S-VECD) tests. Pavement performance prediction is carried out using the results from S-VECD approach in the FlexPAVETM software. The test results indicate that the performance of CR is highly affected by the amount of oil distillate percentage in the emulsion as well as the amount of recovered binder in the RAP. While having a relatively lower rutting resistance capability, the CR mixtures maintained an acceptable fatigue performance. As compared with CR mixtures, hot mixed intermediate and base course mixtures indicated better rutting performance while having lower resistance to cracking.
