Effect of Nanosilica on the Mechanical and Microstructural Properties of Wood Ash Concrete

The South African cement industry is under mounting pressure to reduce carbon dioxide emissions associated with cement and concrete production in line with sustainable development goals.This study investigates the effects of Nanosilica-wood ash mixture on the mechanical and microstructural properties of wood ash cement concrete, with the aim of advancing alternative and sustainable cement production methods.In this research, control concrete sample with Ordinary Portland Cement (OPC), lacking Nanosilica and wood ash is represented as CC.The experimental groups, denoted as Zawa 05-15, utilize South African wood ash as a partial replacement for cement at varying proportions of 5%, 10%, and 15% by weight of cement.The investigation encompasses an analysis of the chemical composition, specific gravity, and particle size distribution of the wood ash, as well as the fine and coarse aggregates used in the concrete mix.The study evaluates the workability, compressive, splitting tensile strength and microstructure of both the plain and composite concrete samples.The findings reveal a noteworthy enhancement in mechanical properties upon the introduction of Nanosilica mixed with wood ash.Moreover, the microstructural characteristics of the concrete are notably improved with the incorporation of Nanosilica mixed with wood ash.Notably, a maximum of 38,8 MPa and 1,3 MPa is attained for both compressive and splitting tensile strength respectively at the 14-day curing period when 15% wood ash is added to the concrete mix.In conclusion, this research establishes that the addition of Nanosilica mixed with wood ash significantly enhances the mechanical and microstructural properties of wood ash cement concrete.The optimum level of wood ash addition for these improvements is determined to be 10% for compressive strength compared to the control sample strength.This research addresses the need to lower carbon emissions in the cement industry in South Africa by utilizing wood ash and Nanosilica in the development of sustainable cement production methods.The findings thus offer more scientific and technically feasible information to further develop sustainable concrete in civil engineering construction.