Fundamental Properties of Mortar Containing Waste Concrete Powder

Waste concrete is usually caused to recover its ingredients, and is then divided into a coarse fraction, while contains mainly the coarse aggregate, and a fine fraction, which consists of a mixture of hydrated cement and aggregate fragments. Waste concrete powder (WCP), we studied, contained more than 40% of insoluble ingredients, while its chemical composition appeared similar to that of cement. Containing cement hydration products which include capillary pores, the specific gravity of the WCP was in the range of 2.4 similar to 2.6. Flow value of fresh mortar with WCP was reduced due to pores within the hydration products absorbing the mixture water, and it is difficult to measure the flow value of mortar containing WCP 30%. Compressive and flexural strength at 7 and 28 days of mortar with WCP were smaller than those of the control mortar without the WCP, because of the dehydraed cement within the WCP. In addition, the compressive and flexural strength of the mortar containing the WCP2 30% appeared to be reduced 32% and 15% at 28days compared to the mortar with only cement, respectively.