Fly-ash-blended Lean Concrete Mixes For Concrete Blocks

摘要

Fly ash is used to improve the properties of concrete in both fresh and hardened states. This study was focused on the characteristics of fly-ash-blended lean concrete mixes suitable for production of solid concrete blocks used for masonry walls and for non-structural applications. The influence of superplasticiser and low calcium fly ash on the workability of two lean concrete mixes was examined. Replacement of both cement and sand by up to 50% fly ash was attempted. The compressive strength and fly-ash content relationships for the two lean concrete mixes were obtained. Maximum compressive strength was obtained for 10% cement replacement and 40% sand replacement by fly ash. The strength increased by two to three times when compared with concrete without fly ash. Similar enhanced strength for masonry was also observed for blocks with fly ash. The maximum flexural bond strength of masonry was for masonry couplets using blocks having 10% cement replaced by fly ash. The study showed that addition of fly ash to lean concrete mixes significantly enhanced the strength of the concrete.