Investigating the Effect of Asphalt Ageing on the Mechanical Properties of Asphalt Mixtures Made by Limestone and Siliceous Aggregates

In this research the effects of different aging conditions on the raveling and cracking resistance of asphalt concrete made by two types of aggregates, namely limestone and siliceous source have been investigated. Asphalt samples made by siliceous and limestone aggregates were made and were subjected to short-term and 5 and 7-day long-term aging conditions. After that, they were tested using Cantabro mass loss and semi-circular bending test at ambient temperature. Results reveal that the mixture made by limestone aggregates has more raveling and cracking resistance than the mixture made by siliceous aggregates. These results were found to be due to rougher texture and more angularity of limestone particles and also having more MgO and CaO content in their chemical compositions. Results also reveal that aging results in reduction of raveling resistance, fracture energy, fracture toughness, ductility and critical load sustained before fracture in semi-circular bending test. The effect of aging on these properties was found to be dependent on the type of aggregates and the considered property. In terms of raveling resistance, the aging is more effective on the mixture made by limestone aggregates; however, the fracture properties and cracking resistance of the mixture made by siliceous aggregates are more affected by aging than the mixture made by limestone aggregates.