Effect of Petrography of Aggregate on Rutting Behaviour of Asphalt Mixture

Pavement failure occurs mostly due to poor selection of aggregate, which is highly dependent on aggregate petrography. The limited number of studies has been carried out in the past to relate the minerology of aggregate with the asphalt mix performance. This research aims to link the minerology of aggregate to the rutting of the asphalt pavement. In this study three different quarries of aggregates were collected for study i.e., Pathargarh, Surajgali and Murunj, Pakistan. Physical and mechanical properties of selected aggregate were determined before preparing the mix design. Aggregate properties were well within the limit specified by National Highway Authority (NHA). Then performance tests i.e., Hamburg wheel tracker test were performed on the asphalt mix to determine the rutting. The results showed that Pathargarh and Surajgali aggregate contains 96 and 95 percent carbonate making it basic. In contrast 84 percent quartz were found in Murunj aggregate. Rutting value of Pathargarh is better followed by Surajgali i.e., 3.43 mm and then Murunj 8.63mm. This study concludes that carbonate aggregate has rough texture making it better adhesion with bitumen, while quartz has poor adhesion with bitumen due to its smooth texture making it more susceptible to rutting.