A transition towards circular economy with the utilisation of recycled fly ash and waste materials in clay, concrete and fly ash bricks: A review
Aswin Kumar Krishnan, Yat Choy Wong, Zipeng Zhang, Arul Arulrajah
Abstract
Coal burning in power plants is considered an energy-intensive process that increases carbon emissions and generates numerous tonnes of fly ash materials. Incorporating fly ash disposal into bricks is regarded as an effective approach for achieving net-zero goals in 2050. This recycling approach can mitigate the waste stockpiling and conserve millions of tonnes of resources annually. Researchers have conducted numerous studies about fly ash in bricks, however, a systematic review of bricks containing fly ash is yet to be published. This review presents a comprehensive analysis of studies on incorporating fly ash in clay-fired bricks and blending fly ash with waste materials in concrete bricks. The results highlighted that fly ash incorporation in clay bricks at low temperatures is considered an effective pathway because of its high compressive strength and low water absorption which contributes to overall environmental benefit owing to reduced energy consumption. In addition, it was found that fly ash-based concrete bricks can be an essential product in the construction industry because of their high performance, reduced carbon emissions and low material cost. This review highlights the potential benefits of fly ash and its potential industrial utilisation including agricultural applications across the globe. • Fly ash and waste materials utilised in clay and cement bricks were explored. • Fly ash is a viable resource that could potentially impact the building sector in positive ways. • Firing temperatures in clay and fly ash bricks are discussed in detail.