Preliminary mechanical characteristics of asphalt concrete mixture containing RAP as the design of sustainable mixture

Abstract

An asphalt pavements require to a wide variety of raw materials, costs and energy in a construction and repair processes. The using of recycled and waste materials in the pavement industry is one branch of the sustainability policy which is leading to substantial reductions in material, cost, and energy, as well as environmental enhancement. This research aims to evaluate the impact of reusing RAP materials in the production of recycled asphalt mixtures and investigate the mechanical characteristics depending on the criteria of mixture strength under affecting various testing conditions as a sustainable design method. Three proportions of RAP materials (12.5, 25, and 50 %) were added to two types of mixtures these used in surface and base layers. one type of softening agent (vacuum residue liquid asphalt) was used to restore the RAP binder properties. Several laboratory experiments were carried out on the control and recycled asphalt mixtures such as Marshall stability and flow, indirect tensile strength and the resilient modulus. The results indicated that the adding of RAP materials with virgin binder resulted in improving the strength and mechanical properties of recycled asphalt mixtures, while the using of vacuum residue liquid asphalt as a softening agent in recycled mixtures has given impressive results in improving the durability and workability.