Performance of Fine RAP Concrete Containing Flyash, Silica Fume, and Bagasse Ash

Abstract

In the present study, the adverse effect of dust on the properties of concrete containing 75% fine reclaimed asphalt pavement (RAP) (75F) (obtained using an uncontrolled milling technique) is minimized by using higher doses of superplasticizers (SP) in combination with silica fume (SF), flyash (FA), and bagasse ash (BG). It was found that the 75F mix requires at least double the amount of SP to achieve the recommended slump value. Moreover, improvement in the fresh state was found to enhance the hardened properties of the 75F mix significantly. Inclusion of the considered mineral admixtures was found to further enhance the compressive strength, splitting tensile strength, and abrasion resistance; however, inclusion of BG and FA resulted in comparable flexural strength. The determination of water absorption and permeable voids was found to be affected by the asphalt film, suggesting this testing should be conducted at a temperature lower than 5°C. Based on the results of the economic analysis, the addition of extra doses of SP should be considered as the best and most economical way of minimizing the effect of dust present in fine RAP aggregates, whereas inclusions of BG and FA could further make the concrete cheaper and more durable.