Experimental Investigation of New Substitute Brick for Brick Bat Coba

Brick Bat Coba (BBC) is a popular traditional waterproofing method in India, which is mainly employed on flat concrete roofs. The efficacy of the system to a great extent relies on the masonry unit type employed in the system. This study examines the performance of different masonry units that is, Red Burnt Bricks, Fly Ash Bricks, and Autoclaved Aerated Concrete (AAC) Blocks, in BBC applications. By experimental testing and site observation, Red Burnt Bricks were discovered to possess better performance in durability, bonding strength, and water resistance and are very suitable for BBC. AAC Blocks, on the other hand, exhibited high water absorption and unacceptable bonding with mortar, resulting in void occurrence and leakage possibility, which renders them not suitable for waterproofing purposes. Fly Ash Bricks exhibited moderate performance. Cost analysis further showed Red Bricks to be the most affordable choice, with AAC Blocks being much more costly. Further, Thermal analysis indicate that the Fly Ash Brick has optimum thermal resistance with minimum peak temperature and average cooling, making it more appropriate for thermal insulation than Red and ACC Bricks. Index Terms— Brick back coba, density test, compression test, thermal test