EFFECTS AND BENEFITS OF USING HIGH CONTEN T OF FLY ASH IN CONC RETE

The us age of fly ash products by the South African cement and construction industries has saved the country over 6 million tons of harmful greenhouse gas emissions. T he re cycling of it as cement extenders provides an immediate benefit for the environment while still improving the quality of concrete, and increasing the amount used in concrete can promote sustainable development. This study evaluated properties of 35MPa /9,5mm concrete with fly ash substituted at 30%, 40%, 50% and 60 %. Increasing the fly ash content can result in more workable and less permeable concrete. The compressive strength and durability index results showed that the fly ash content can be increase d beyond 50% and still achieve the required strength and produce durable concrete. Substituting high volumes of cement with fly ash in concrete can provide good quality concrete and a relief to the environment without compromising the quality and cost of c oncrete