Reclamation of fly ash and crumb rubber in clay bricks using sodium metasilicate at low curing temperature

This research study was to investigate fly ash (FA) and crumb rubber (CR) in clay bricks using sodium metasilicate at low heating temperatures which is an emerging trend in the construction industry to eliminate landfill depletion problems. The fly ash weight ratios studied was at 5, 10, 15, 20 and 25%, while the crumb rubber weight ratios was fixed at 1% for all the samples. During previous study, the initial temperature of 50°C for 48 hours was conducted. In this study, the curing temperature was increased to 60°C for 72 hours. Then, the temperature was raised further to 160°C for 24 hours to obtain the best optimum curing conditions. The sodium metasilicate powder was used as a solid activator for the alkaline activation of FA and CR. The varying weight ratios of Na 2 SiO 3 was at 2.5, 5, 7.5 and 10%. Compressive strength, cold water absorption, linear shrinkage, initial rate of absorption and thermal conductivity were tested and compared with the properties of clay bricks. The surface morphology of FA and CR blends was examined using scanning electron microscopy. Furthermore, the different Na/Si ratios were identified using EDS analysis. The experimental results indicated that the highest compressive strength of 11.7 MPa was achieved with 25% FA + 1% CR using 10% Na 2 SiO 3 . It was found that thermal conductivity satisfied the requirement for the standard bricks except for 10% FA + 1% CR at 10% sodium metasilicate. The high porosity in bricks resulted in low thermal conductivity, which is an excellent thermal insulation property of the bricks. This study demonstrates the potential benefits of using fly ash and crumb rubber using sodium metasilicate powder in green buildings could reduce the extraction of natural resources and improve disposal efficiency. • The mechanical performance of fly ash and crumb rubber in clay bricks were analysed using low-temperature curing. • The addition of sodium metasilicate powder is necessary to improve the compressive strength of the clay bricks • Fly ash and crumb rubber could be an excellent substitution for the clay bricks.