Effect of ceramic waste powder on alkali-activated slag pastes cured in hot weather after exposure to elevated temperature

Abstract

Extensive amounts of ceramic and slag wastes are produced every year by ceramic and iron industries. Recycling of these wastes are one of the operational solutions to eliminate their disposal. It is appropriate to employ these wastes as a binder material in the field of construction to save the virgin natural raw materials and limit environmental pollution problems. This work aims to incorporate ceramic waste powder (C–W–P) into alkali-activated slag (AAS) pastes activated with sodium silicate. The specimens were cured at a high ambient temperature of 45 °C to simulate curing in hot weather. Slag was partially replaced with C–W–P in the range of 5–50%, by weight. The effect of C–W–P on the workability, water absorption and compressive strength were measured. After 91 curing days, some specimens were subjected to elevated temperatures in the range of 200–1000 °C with a step of 200 °C for 2 h and the residual compressive strength was monitored. The results were analyzed by X-ray diffraction (XRD), thermogravimetric analysis and its derivative (TGA/DTG) as well as scanning electron microscopy (SEM). The results revealed that C–W–P has a negative effect on the workability, whilst it has a positive effect on the water absorption as well as the compressive strength before and after exposure to elevated temperatures.