Determining the Potential of HMA Mixtures Containing Polymeric and Mineral Additives against Moisture Damage

Moisture susceptibility, mechanical deformations, freeze-thaw cycles and penetration (in winter maintenance operation) into asphalt mixture are important mechanisms that cause various failures in asphalt pavements. In recent years, using polymeric sulfur compounds (Googas) has been the focus of attention for many researchers due to the ease of availability and low cost, as well as the observance of environmental principles. Based on the previous studies, it has been found that asphalt mixtures containing Googas are weak in the presence of moisture. In this research, the effects of hydrated lime and sasobit additives on moisture susceptibility, mechanical strength and resistance against freeze-thaw cycles in asphalt mixtures containing Googas have been investigated. First, the mentioned aggregates, bitumen and additives were prepared and the required tests were performed on them. After determining the optimum bitumen percent by Marshall method, the moisture susceptibility, mechanical deformations and resistance against freeze-thaw cycles of asphalt mixtures were examined using parameters of tensile strength ratio (AASHTO T-283) and Marshall quotient (ASTM D-1559). Based on the results obtained from the tests, it was found that sasobit additive effectively improved the resistance of control asphalt mixtures, and mixtures containing Googas, against moisture and freeze-thaw cycles. However, hydrated lime additive had no significant impact on improving the items mentioned characteristics. In general, and statistically, asphalt mixture containing 30% Googas and 1.5% sasobit offered the best result in improving the resistance of asphalt mixtures against destructive effects of freeze-thaw cycles.