Effect of Steel Fibers on the Properties of Concrete

An attempt has been made to study the effect of steel fibers on the compressive and flexural behavior of conventional concrete. Thirty cubes and 10 flexure beams were cast, out of which three cubes and a flexure beam belonged to the control mix. The variables in the study were aspect ratio (15, 25, and 35) and vol% fraction of fibers (0.25, 0.50, and 0.75). A marginal improvement in the ultimate strength was observed due to the addition of fibers. The optimum volume fraction of fibers for better performance in terms of strength and ductility was found to be 0.5%. Accelerated curing was adopted for all the specimens. Indian standards give only the correlation of 28-day characteristics compressive strength from the accelerated compressive strength. There is no relationship between the 28-day flexural strength and accelerated flexural strength. Hence an analytical model representing the relationship between 28-day flexural strength and accelerated flexural strength was suggested. Also models for compressive strength and flexural strength for varying aspect ratio and percentage of volume fraction were given.