Evaluation of the durability and the performance of an asphalt mix involving Aramid Pulp Fiber (APF): Complex modulus before and after freeze-thaw cycles, fatigue, and TSRST tests

The main deteriorations of asphalt pavements in cold regions are due to the effect of heavy traffics, water action, low-temperature fluctuations, freeze-thaw cycles and the combination of all these factors together. Fiber additives are mainly used as reinforcement materials in asphalt pavements to improve the tensile properties and increase the strength against low-temperature cracking and potholes. Aromatic polyamide fiber (aramid fiber) is used in advanced composite materials since it has a very high tensile strength, modulus, and high cohesiveness. Whether the addition of Aramid Pulp Fiber (APF) can effectively improve the fatigue life, thermal performance, and durability of asphalt mixture under repeated freeze-thaw cycles are also major problems needed to be investigated properly. In this regard, thermo-mechanical analyses (complex modulus, fatigue, and thermal stress restrained specimen test (TSRST)) have been conducted on the asphalt mix with a nominal maximum aggregate size of 20 mm, known as Grave Bitume (GB20) in Quebec, Canada. The improvement effect of APF incorporation is assessed to compare the stiffness variation before and after 300 rapid freeze-thaw cycles, fatigue behavior, and thermal strength. The results indicate the ability of APF to increase the durability of the GB 20 mix against freeze-thaw cycles. The TSRST and fatigue results also show that the APF additives can increase the performance of the GB 20 mix against low temperature cracking and heavy truckloads.