Short-Term and Long-Term Effects of Cement Kiln Dust Stabilization of Construction and Demolition Waste

High volumes of construction and demolition waste (CDW) are continuously produced worldwide. The European Commission aims to increase the recycling of nonhazardous CDW to a minimum of 70% in weight terms by 2020. Hence, there is increasing pressure on researchers to focus on the valorization of these alternative materials for use in the world of construction alongside traditional materials. CDW contains materials from excavation and/or demolition and are typically heterogeneous in terms of composition, grain size, and toughness; furthermore, some particles are more sensitive to degradation processes than others. One solution for an increase in durability while maintaining sufficient strength levels is chemical stabilization with cementitious binders. The paper illustrates the results of a laboratory investigation into the properties of CDW when subject to stabilization with cement kiln dust (CKD). Mixtures of CDW stabilized with ordinary portland cement (OPC) were prepared for comparison purposes. The results obtained with CKD are encouraging because it increases the strength and stiffness of CDW, thus leading to a material completely made up of recycled wastes and by-products usable in the formation of pavement subbases and subgrades. As regards the curing time, all mixtures saw a significant increase in their mechanical parameters when passing from 7–28 days to 365 days of curing.