Effects of active waste powder obtained from C&D waste on the microproperties and water permeability of concrete

Abstract

Using waste powder (WP) derived from construction and demolition (C&D) waste as supplementary cementitious materials in the preparation of waste powder concrete (WPC) provides a new way of reclaiming C&D waste. This paper focuses on investigating the microproperties and the water permeability of the WPC. A series of micro experiments and water permeability related tests were conducted. The results show that the elements and compound compositions of WP are similar with those of cement and fly ash. The addition of high fineness WP promotes the hydration rate and improves the pore structure of WPC due to its microaggregate filling effect. The incorporation of WP decreased the workability and drying shrinkage behavior of WPC, and the WPC with up to 30%WP has a satisfied compressive strength. The water permeability of the WPC, under capillary absorption and pressure, is lower than that of the control group, and the WPC with approximately 30%WP has the lowest water permeability. Subjected to the harsh environment of freeze-thaw cycles and applied loading, the addition of WP increases the sensitivity of the WPC to the imposed damage and water permeability. Although the imposed damage increases the water permeability of the WPC, incorporating appropriate content of WP leads to a lower water permeability of WPC than that of the control group when the exposure condition is the same.