Effect of Fly Ash on Compressive Strength of Mortar and Brick Aggregate Concrete

Abstract

This paper presents tse influence of fly ash on compressive strength of mortar and brick aggregate concrete. A lot of tests were done about strength of fly ash concrete all over the world. In those experiments, stone chips were generally used as coarse aggregate. In this experiment locally available materials such as burnt clay brick chips as coarse aggregate, sand and fly ash available in Bangladesh (Indian fly ash) were used. Compressive strength of mortar and concrete were tested as per ASTM C-109 and ASTM C39 respectively. Here nine different types of both mortar and concrete specimens were prepared based on w/c ratio and percent of fly ash replacement. It is noted that generally fly ash mortar and concrete gain strength slowly at early ages (up to 28 days) but they gain strength almost equal to plain mortar and concrete at later age (at 90 days). As fly ash is low cost material and fly ash mortar and concrete attain almost equal strength to plain mortar and concrete at later age, fly ash is to be used in mortar and concrete to reduce the construction cost.

Keywords: Compressive strength, OPC, brick aggregate, fly ash, w/c ratio, hydration