Investigation of Grooving Potential and Modulus of Resistance of Rubber Asphalt Mixture Containing Parafiber Fibers

In the past decades, many researchers have tried to improve the properties of bitumen and use such bitumen in asphalt mixtures. Adding rubber powder to bitumen and producing rubber asphalt creates desirable properties for the asphalt mixture, which will be a step towards moving towards sustainable development and environmental protection. The main disadvantage of this type of asphalt mix is ​​the increase in mixing temperatures and density, thereby increasing construction costs and difficulty of execution. In this research, the effect of semi-hot paraffin additive on reducing the mixing temperature of rubber asphalts has been investigated. Bitumen was mixed with two different percentages of 8 and 16 percent of rubber powder and modified with three different percentages of 1, 2 and 3 percent by weight of paraffin additive asphalt mixture. Also, samples of asphalt mixture were prepared and then compacted at two mixing temperatures of 130 and 150 degrees by Marshall method. To evaluate the performance of the asphalt samples, Marshall tests (strength and fluidity), dynamic creep and resilience modulus were performed. The results of modulus test showed that by adding rubber powder to asphalt mixtures as well as increasing the fiber modulus, the modulus increases. The results of dynamic creep test also showed that at a mixing temperature of 150 °C the furrowing resistance was better than the control samples. However, at a mixing temperature of 130 °C, the grooving resistance is reduced. The results also showed that increasing the percentage of parafiber improves the corrosion resistance of rubber asphalts.