Clay-burnt course aggregate: Production and utilization in concrete

Abstract

Scarcity of natural aggregates in Bangladesh has led the construction industry to rely prominently on crushed brick coarse aggregates. The crushing procedure involves material waste and lacks means to control the grading, which results in poor quality concrete. These drawbacks could be addressed if graded aggregates could be made by burning clay. With this background, suitable soil was sampled, molded and burnt at high temperatures (850°C, 900°C, and 950°C) to make clay-burnt coarse aggregates (CBCA) of different sizes (20 mm, 15 mm, 10 mm and 5 mm). Physical properties of the aggregates were investigated and cylindrical concrete specimens were made with both CBCA and other locally available aggregates. Aggregates produced at 950°C showed better aggregate properties compared to first class brick aggregates. CBCA made concrete resulted in higher compressive strength compared to stone and brick aggregates. Direct production of CBCA has the potential to enhance overall construction quality in Bangladesh.