Environmental and Mechanical Investigation of Sustainable Lightweight Aggregate Concrete

Reducing the density of concrete has received remarkable attention as the loads carried by structural elements are significantly contributed to the weight of concrete. This has led to an increasing request for structural lightweight aggregate concrete (LWAC) due to its numerous pros including lower density and better thermal and acoustic performance, etc. In this regard, a range of lightweight materials including lightweight expanded clay aggregate (LECA) have emerged as a contender for reducing the density of the concrete. In addition, today’s concrete is expected to satisfy stricter eco-efficiency and sustainability demands, causing a need for alternative binder material to replace (in part or in full) the high carbon dioxide (CO2)-generating traditional ordinary Portland cement (OPC). The use of silica fume (SF) as partial substitution of OPC is a promising solution to mitigate the negative effects of OPC production. Therefore, this work aims to analyze the influence of material parameters on the mechanical and environmental behavior of LWAC. To achieve this objective, a total of 30 LWAC mixture designs varying OPC content, LECA percentage replaced with natural aggregates, SF partial replacement by weight of OPC, and varied water-to-cement (w/c) ratios as the test variables were examined. A sensitivity analysis, a simulation tool used to understand the impact of changes to input parameters on the outcome, was used to determine the effect of diverse variables on the compressive strength and CO2 emission of LWAC mixture.