An ecological composites for a novel class of solid waste concrete.

• The activity index of solid waste based composites is higher than 95%. • Solid waste based composites can replace 40% cement in concrete. • The total amount of solid wastes in concrete is up to 83%. Waste rock is stripped from open pit iron mines, which is often used to prepare aggregate in concrete because of its stable performance. However, with the continuous improvement of aggregate performance, a vast amount of stone powder produced in the process of aggregate preparation causes secondary solid waste pollution. In this paper, the feasibility of preparing supplementary cementitious materials (SCMs) by using solid waste based composites was investigated. The results show that the 28-d activity index of iron ore waste powder (IOWP) based admixture is higher than 95%, and when it is used to replace cement in concrete, the admixture can reach 40% and the performance of concrete is stable. When iron ore waste completely replaces aggregates and IOWP based admixture replaces part of cement for concrete, the solid waste content of solid waste aggregate concrete (SWAC) is up to 83% compared to natural aggregate concrete (NAC). This study provides a new idea for high value, high efficiency and scale development of solid wastes. [ABSTRACT FROM AUTHOR]