Rheological properties of bituminous mastics containing chemical warm additive at medium temperatures and its relationship to warm mix asphalt fatigue behavior

Previous research studies have proved the beneficial effects of Zycotherm on durability and moisture resistance of asphalt mixes. This study was performed to investigate the long-term performance of bituminous mastic and asphalt mix containing this additive in terms of fatigue behavior. The shear modulus and phase angle master curves of bituminous mastics were developed at 20 degrees C using the results of frequency sweep DSR test at four temperatures of 13, 19, 25 and 31 degrees C. Then, the time sweep test was accomplished at 20 degrees C to examine the fatigue resistance of asphalt mastics. The micro-structural behavior of mastics were analyzed by atomic force microscopy test. The fatigue behavior of asphalt mixes designed with the same additive contents to mastics were performed by indirect tensile fatigue test at 20 degrees C. The results of time sweep test demonstrated that the addition of Zycotherm up to 0.14% by weight of bitumen, had no detrimental effects on mastic fatigue resistance. It has been recognized from topographical analysis that the micro-structural behavior of Zycotherm containing mastic was highly similar to that of the base one. The variations were came from the difference in the mixing temperature during the preparation of conventional and Zycotherm containing mixtures. (C) 2019 Elsevier Ltd. All rights reserved.