Reduction of Bitumen Content and Production Temperature of Hot-Mix Asphalt Incorporating RAP Using Dune Sand and Lime

Abstract

Using Reclaimed Asphalt Pavement RAP allows monetary savings with reduction of the quantity of greenhouse gases and consumption of natural resources (aggregates and bitumen). Dune sand is an abundant material in many worldwide regions. Due to its mineralogical composition and fineness, it has many interesting mechanical characteristics. In addition, lime has been increasingly used in asphalt mix formulations because it contributes in resisting rutting and aging problems of asphalt mixes by limiting the oxidation of bitumen. The paper discusses the effects of incorporating dune sand and lime on the bitumen content and production temperature of bituminous mixtures incorporating (RAP). The main objective is to increase the (RAP) rate to increase the level of the cited benefits. Different percentages of RAP (10–50%), dune sand (5–10%) and lime (0.5–1%) were evaluated. Mixtures’ gradations have been carefully studied in order to respect existing specifications. Results showed that the addition of 10% dune sand reduces the bitumen content by 0.3%. The addition of lime has improved the binder/aggregates adhesion, while the gain in bitumen content and mechanical performances were established. The addition of dune sand and lime have reduced the production temperature to approach that used when manufacturing warm-mix asphalt. The complex modulus tests, carried out at different temperatures and frequencies, have shown that the new formulated mixes perform better than conventional mixtures.