2.2. Lightweight aggregates (LWAs)
Three types of LWAs viz., diatomite aggregate (DA), pumice aggregate (PA), and
recycled aggregate from autoclaved aerated concrete (RA) were used as coarse
aggregates. DA was taken from Lampang province in the north of Thailand. It was
calcined at 800 C for 4 h to reduce clay mineral [17,18]. Commercially variable
acidic pumice was used as PA. RA was broken autoclaved aerated concrete blocks
obtained from construction site. All types of aggregates were crushed and sieved
into the same particle sizes of 4.8–9.5 mm. The coarse aggregates were prepared
in saturated surface dry (SSD) condition before the mixing to maintain the same
flow value of cement paste of 170–180 mm and to prevent cracking problems
due to the water absorption of aggregate [19–21].