Recylced Asphalt Pavement as Course Aggregrate Replacement in High Strength Concrete Mixes

Many new construction materials utilizing recycled or bi-product waste have recently been developed to help create "greener" construction. One of these materials utilizes recycled asphalt pavement (RAP) as a replacement for a portion of the course aggregate in concrete mixes. Previous studies on these concrete mixtures has shown that the RAP inclusion considerably lowers the compressive strength of the concrete; thus limiting its usefulness. However, the inclusion of RAP in high strength concrete mixes has yet to be studied. Additionally, most of the previous studies have replaced the course aggregate only by weight and not by weight and gradation and have taken the RAP from only one source. This study considers several factors that may affect the strength of concrete mixes that utilize RAP as course aggregate replacement. First, the variability in compression strength is studied to determine if geography and environmental conditions of the RAP harvest location affects the mechanical properties. Then, six separate RAP replacement percentages are studied to determine an ideal replacement amount and the relationship between RAP replacement to compressive and tensile strength. This study also presents the results of gradated versus non-gradated RAP replacement in high strength concrete mix.