Lightweight Aggregate concrete has been proven to be able to reduce the self-weight of a structure. An experimental study was undertaken using lightweight scoria aggregate concrete (LWSAC) aiming to determine the viability of scoria being used in structural concrete.
Bulk density, water absorption and a sieve analysis was conducted on the scoria aggregate prior to mix design for concrete. LWSAC has produced a compressive strength of 30.50MPa at 28 days compared to the control concrete had 38.93MPa. Replacing 15% of Portland cement using fly ash has increased the compressive strength to 41.14MPa at 28 days.
Nevertheless, replacing 10% of Portland cement by silica fume, the compressive strength of LWSAC has decreased with the time. Although, high water absorption property of aggregate may have contributed for a relatively high drying shrinkage, it is still within an acceptable limit for general purpose concrete. Therefore it can be concluded that scoria can be used to produce structural concrete with a relatively low density.
Source: RMIT University
Authors: I Lau | S Setunge | N Gamage