Evaluation of developed alkali-activated bricks for energy-efficient building construction

Abstract

Gradually, the temperature of the earth is increasing due to global warming, which has increased the operational energy demand in buildings. This energy usage can substantially be reduced using energy-efficient measures such as developing a thermally resistant building envelope. The building envelope mainly consists of walls, roof and floor, where walls play an important role in heat transfer that is a major contributor to operational energy demand. In this study, a walling material (alkali-activated bricks) was developed, where locally available industrial wastes (co-fired blended ash and stone dust (CBA-SD)) were activated by a sodium-based alkali activator and cured at an ambient temperature of around 37°C. The alkali-activated bricks were evaluated for mechanical-, physical-, thermal- and durability-related properties that are in accordance with Indian standards. The results showed that the developed alkali-activated bricks are lighter in weight and have lower thermal conductivity (0.35–0.4 W/(m K)) as compared to conventional fly-ash (FA) bricks (1.05 W/(m K)). A case of a residential building with varying building envelope and number of floors was simulated for analysing building performance using a computational approach. As compared to FA bricks, the CBA-SD brick model resulted in peak cooling load reduction by 49–51, 46–48 and 44–46% for single-, two- and three-storeyed buildings, respectively.