Sustainable Lightweight Concrete Made of Cement Kiln Dust and Liquefied Polystyrene Foam Improved with Other Waste Additives

Abstract

The main objective of this study is to mix two problematic wastes, cement kiln dust (CKD) and polystyrene waste liquified by gasoline, to produce a new lightweight cementitious material, as a green composite used in the construction industry. Various ratios of liquified polystyrene (LPS) were blended with CKD to achieve the optimum mixing ratio in the absence and presence of different additives. A significant improvement of mechanical properties (compressive strength of 2.57 MPa) and minimization of the porosity (51.3%) with reasonable water absorption (42.4%) has been detected in the mixing of 30% LPS with CKD due to filling the voids and gaps with liquified polymer. Portland cement, waste glass, and iron slag have been incorporated into CKD-30% LPS paste at different mass fractions of 0%, 5%, 10%, 15%, and 20%. However, a considerable value of compressive strength up to 2.7 MPa was reported in presence of 15% of any additive material with CKD-30% LPS matrix. This study recommends implementing a viable strategy to upcycle any of the examined wastes of the optimum ratios (15% waste glass or iron slag with 30% of LPS) together with another hazardous waste, namely cement kiln dust, to produce lightweight cementitious bricks in eco-friendly sustainable technology.