| Popis: |
With the cement industry responsible for about 7% of anthropogenic greenhouse gas emissions globally, the use of supplementary cementitious materials for construction can provide a partial solution. Research reports that it would take about 1.58 billion tonnes of supplementary cementitious materials (SCMs) used annually to eliminate 1 billion tonnes of CO2 from the processing of cement. Rice husks are agricultural waste materials produced in tropical countries. In Nigeria, up to 8 million tonnes of rice are produced annually, of which 20–23% are rice husks, which are landfilled and take a long time to biodegrade thereby constituting land pollution. This study focuses on the use of these landfilled rice wastes, which have no economic value, to address the negative impact of cement production and the excessive production and disposal of this waste material. The research employed an experimental study to investigate the effect of rice husk ash on masonry blocks. Rice husks were burnt in a controlled manner, and the RHA obtained was characterised via X-ray diffraction and X-ray fluorescence to quantify its physicochemical properties. Density, compressive strength, water absorption, and strength activity index were determined after 28 days of curing. Thermal characterization shows up to 18% improvement in the thermal resistance of the blended masonry unit with 15% RHA additions weight of cement. The effect of this on the building envelope will be substantial in terms of building energy consumption to address heat gains or losses through the building envelope. Also, the reuse of this waste material for low-carbon construction will help address the negative impact resulting from cement production and utilisation by the building industry, reduce landfilled waste, and also encourage a circular economy. Furthermore, this study will contribute to existing knowledge on affordable building materials and provide a solution to the massive housing deficits in Nigeria. |
