Characterization of Recycled Coarse Aggregate (RCA) via a Surface Coating Method

Abstract

Recycled coarse aggregate (RCA) made from waste concrete is not a suitable structural material as it has highabsorption of cement mortar, which adheres on the aggregate surface and on the tiny cracks thereon. Therefore, when using RCAmade from waste concrete, much water must be added with the concrete, and slump loss occurs when transporting. Hence, itsworkability is significantly worse than that of other materials. In this study, surface of RCA was coated with water-solublepolycarboxylate (PC) dispersant so that its characteristics improved. Each possibility was evaluated: whether its slump loss can becontrolled, by measuring its workability based on the elapsed time; and whether it can be used as a structural material, bymeasuring its strength. Moreover, the carbonation due to cement mortar adhesion was measured through a carbonation test. As aresult, RCA coated with PC dispersant was found to be better than crushed coarse aggregate and RCAwhen the physical propertiesof the fresh concrete and the mechanical, durability of the hardened concrete were tested.