Properties of Portland cement mortar incorporating white cement bypass dust

Huge quantities of white cement bypass dust (WCBPD) are accumulated annually in large heaps in the neighborhoods of different white cement factories in Jordan; posing an environmental threat and adding additional cost for its disposal. In this study, the potential of using this byproduct in concrete industry is investigated. Cementitous mortar mixtures were prepared at two water-to-binder (w/b) ratios of 0.45 and 0.60 without and with cement or sand replacement by WCBPD at percentages from 5% to 20% (by mass). The fresh and hardened properties of various mortars were studied including normal consistency and setting time, compressive strength, drying shrinkage, and capillarity absorption. In addition, the sulfate-resistance of these mortars was investigated. The results were promising with regard to using WCBPD as a partial replacement of sand especially for blend mortars at the lower w/b ratio, yet revealed limited potential of using such dust as a partial replacement of cement; especially at contents greater than 5%. The setting time was significantly reduced, capillarity absorption and drying shrinkage increased whereas sulfate resistance reduced upon incorporation of WCBPD as a partial replacement of cement.