Waste coal cement concrete for sustainable production

Abstract

Concrete industry aims to mitigate its environmental footprint and provide cost-effective approaches for the promotion of sustainable development goals. Waste utilisation in concrete production could satisfy sustainability credentials. However, performance of waste incorporated mixes is not fully clear which limits the use of waste materials. Thus, a clear quantitative evaluation cannot be established.Locally obtained waste coal ash (WCA) was used in this study as a replacement to both CEM I and CEM II/B-S cements with replacement levels of 10% and 20% to achieve sustainable concrete production. Developed concretes were tested against various engineering properties (slump, density, compressive strength, water permeability and porosity) and sustainability characteristics (social, environmental and economic). A balanced scoring system have been used to evaluate the overall performance of laboratory mixes.Results revealed that WCA use provided similar slump values but reduced the fresh density. WCA mixes had lower compressive strength but enhanced absorption characteristics. Environmental and economic sustainability showed significant reductions while social sustainability indicators (sound permeability and thermal conductivity) showed enhanced performances for WCA mixes suggesting potential use for sustainable construction applications. Overall performances suggest that WCA mixes can improve overall performance by 11% and 15.5% for 10% and 20% replacement levels respectively.