Utilization of Concrete Waste as a Cement Replacement: Influence of Calcination on Reactivity and Performance

Concrete waste is one of the major components of construction and demolition wastes, as well as a material that must be removed in an environmentally safe manner. With the inclusion of concrete waste as a minor additional constituent, the popularity of its utilization has gained importance. This study utilizes concrete waste with replacement ratios of 20%, 40%, and 60%, in both calcined and non-calcined forms. Two different calcination temperatures were applied to see the effect of calcination temperatures. Results show that as the replacement ratio of non-calcined concrete waste increases, mechanical performance decreases. However, calcination enhances the reactivity of concrete waste, and at an optimum replacement ratio of 20%, the compressive strength is higher than that of the reference specimen. After freeze-thaw cycles, specimens with 20% calcined concrete waste exhibit lower compressive strength losses compared to the reference specimen. Regarding the mass losses after freeze-thaw cycles, 20% concrete waste calcined at 950 °C have better performance than reference specimen. This study shows that with a 20% replacement ratio, calcined concrete waste can be used as a cement replacement material.