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Influence of Coarse Recycled Concrete Aggregates on the Dynamic Modulus of Asphalt Concrete Mixtures


In the asphalt highway industry, a large number of innovative materials and technologies are explored in order to evaluate their suitability in the design, construction and maintenance of pavements. Billions of tonnes of concrete are extensively consumed in the construction of various structures including buildings, bridges, dams, roads, and others. For constructing the above-mentioned structures, massive amounts of construction and demolition (C&D) waste are generated. A sustainable solution has become highly required and an urgent priority in the asphalt industry to solve various problems including lowering the consumption of virgin materials, decreasing waste materials in landfills and reducing environmental problems, and the utilization of recyclable waste materials, especially recycled concrete. This research is conducted to investigate the possibility of using coarse recycled concrete aggregate (CRCA) in asphalt mixtures. Mix design of HMA mixtures is performed for CRCA at various percentages 15%, 30%, and 60%. After determining optimal asphalt content (OAC) of different mixtures, the stiffness resistance of Ontario Superpave asphalt mixtures is evaluated. Depending on the dynamic modulus test results, the rutting susceptibility and fatigue performance of different mixtures are also estimated. At high temperatures, the obtained results indicate that the use of CRCA can increase asphalt pavement resistance to rutting susceptibility compared to the control mixture. However, this resistance decreases with increasing CRCA proportion in the asphalt mixture. At low temperatures, asphalt mixtures including CRCA have a lower stiffness than the control mixture. This leads to minimizing fatigue and low-temperature cracking. The findings also revealed that the utilization of CRCA in the asphalt mixtures appears to be highly successful.

Conference Paper Details

Session title:
Green Technology in Geotechnical and Materials Engineering
Al-Bayati, H.K.A.