Experimental Study on Properties of Portland Cement Concrete Containing Recycled Asphalt Pavements

Abstract

Although recycled asphalt pavement (RAP) are widely used in the construction of new, and reconstruction of old, hot mix asphalt (HMA) pavements, little research has been done to examine the potential of incorporating RAP into Portland cement concrete to replace virgin aggregate. Because RAP consists of aggregates coated by asphalt cement, the toughness of concrete made with RAP could be improved. In this paper, the mechanical properties of portland cement concrete containing RAP were investigated through laboratory experiments. Two types of RAP (coarse and fine RAP) materials were used to replace the equal amount of virgin coarse and/or fine aggregate. Silica fume and high-range water reducing agent (HRWRA) were also added into concrete mixtures to minimize the strength loss due to the incorporation of RAP. A total of 17 concrete batches were cast and tested for compressive and split tensile strengths, static compressive modulus of elasticity, and toughness index in accordance with ASTM standards. Test results indicated that there was a systematic reduction in the strengths and elastic modulus as well as an increase in the toughness index with the increase in RAP content. While the addition of HRWRA into the matrix improved the mechanical properties of concretes containing RAP, addition of silica fume unexpectedly did not.