Design development of sustainable alkali-activated bricks

Abstract

To meet the ever-increasing housing demand, huge amount of construction materials is being used. This creates a need to design and develop sustainable construction materials. Brick is one of the majorly used building materials that consumes several resources. However, utilization of industrial wastes in the production of bricks could reduce the impact on environment and society. The present study elaborates a design methodology for the development of sustainable alkali-activated bricks using industrial wastes. Bricks were cast by using co-fired blended ash and stone dust (1:1, 2:1 and 3:1 by weight) with alkali-activator (35% of the total dry mix), which consists of sodium hydroxide (8 M) and sodium silicate liquid (1:1). The mix design was fixed by assessing 45 mix trials of various proportions. Developed bricks were evaluated for various physico-mechanical, thermal and durability related properties. Based on the compressive strength (5–15 MPa) results, bricks were categorized into three classes. These bricks have lesser density (1180–1600 kg/m3), water absorption (6–14%) and thermal conductivity (0.35–0.40 W/(m.K)) as compared to commercially available bricks (fly ash bricks and burnt clay bricks). Developed alkali-activated bricks have application in load bearing as well as framed structures. The experimental investigation revealed the potential significance of co-fired blended ash and stone dust in the production of sustainable alkali-activated bricks.