Fabrication and performance evaluation of lightweight eco-friendly construction bricks made with fly ash and bentonite

Abstract

Brick is one of the foremost extensively used construction materials for masonry purpose. Emphasizing the possibility to convey imperative effect against India's present-day lodging and industrial waste concerns are of paramount importance. This could be achieved by fabricating sustainable products using industrial wastes. Alkali-activated products are assumed to be eco-friendly and economical, leading to Portland cement-free products. This project work is an attempt to discover an eco-friendly brick for construction purposes by totally replacing the normal brick components by wastes from many industries. For the investigation purpose, we developed geopolymer bricks by utilizing fly ash as the binder, foundry sand as the fine aggregate, bentonite as an additive for improving its properties and finally the alkaline arrangement (a blend of NaOH and Na2SiO3). Fly ash combines with alkalis such as Sodium Hydroxide (NaOH) and Sodium Silicate (Na2SiO3) creating an alumino-silicate gel, that shows properties similar to that of cement and it can be used as the environment-friendly binding material. The design mix proportions of the current work are 0.54:0.44:0.04 (fly ash: foundry sand: bentonite), solutions to fly ash ratio is 0.5 and the ratio of Na2SiO3 to NaOH is 1.5. The basic characteristics of bricks such as compressive strength, water absorption capacity, density, soundness, efflorescence, and hardness were tested. It attains a compressive strength value ranging between 6-25Mpa, water absorption value in between 5-12% and also the developed bricks were light in weight. Also, the final conclusions were drawn after comparing the test results with other geopolymer bricks and clay burnt bricks. Geopolymer bricks seem to be incredibly beneficial as they will amalgamate a large quantity of industrial wastes. The utilization of waste raw materials (except for alkaline activator solution) resulted in a substantial reduction in the estimated production cost of the bricks.