Geopolymer bricks: The next generation of construction materials for sustainable environment

Abstract

Bricks are one of the most used construction materials worldwide. Conventional bricks are produced by utilizing fertile soil or ordinary Portland cement; both emit greenhouse gases to the environment during production. In an attempt to lessen the brick industry's significant carbon footprint, numerous academicians are working towards the development of innovative and sustainable bricks by utilizing numerous waste materials. This present paper provides an up-to-date review of the development of sustainable and environment-friendly geopolymer brick by utilizing solid industrial waste materials such as fly ash, ground granulated blast furnace slag, red mud, rice husk ash, mine tailings, sugarcane bagasse ash, and municipal solid waste incineration fly ash, respectively. Geopolymer bricks can be produced by the reaction between an aluminosilicate source material and an alkaline solution. The source material can be naturally occurring minerals like kaolinite, clays, etc. or by-product materials such as fly ash, slag, silica fume, metakaolin, rice husk ash, red mud, etc. The sodium and potassium-based alkali material solution can be used as an alkali liquid. Sometimes, the combinations of sodium hydroxide or potassium hydroxide and sodium silicate or potassium silicate solutions or various combinations are used. The selection of raw materials for geopolymer bricks depends on the availability, cost, and type of application. The geopolymer bricks specimen prepared with various waste materials shows excellent mechanical strength (compressive strength, flexural strength) and durability under harsh environments. To manufacture and use bricks from various waste materials on a large scale in a sustainable manner, more research and development are needed. This includes work on standardization, public education about waste reuse and recycling, government policies, etc.