Experimental investigation on the Effect of Superplasticizer on Concrete Containing Recycled Asphalt Pavement (RAP)

In this research, experimental investigation of concrete containing recycled asphalt pavement (RAP) and Superplasticizer (SP) was conducted to study the effect of RAP replacement and SP on some important factors such as slump, water absorption, and density for different concrete mixes. Twenty concrete mixtures were prepared using crushed RAP as a coarse aggregate at different replacement percentages; 0%, 25%, 50%, 75%, 100% by weight of natural coarse aggregate (NA). Superplasticizer dosage varied from 0% to 2.1% (liters per 100 kg of cement). The test results showed that the trend of the relationships of slump and water absorption for concrete with RAP and SP were similar to the traditional concrete (100% NA). Higher slump and water absorption were attained for concrete with higher RAP replacement. In addition, higher SP content revealed higher slump and water absorption. The higher increase in slump and water absorption reached to 38% and 25% respectively compared to control concrete (0% SP). However, more inclusion of RAP aggregate resulted in lower density for concrete and no discernable trend was observed between concrete density and SP content across various RAP replacements.