Experimental Investigation on Impact Resistance of Flyash Concrete and Flyash Fiber Reinforced Concrete

The present Experimental investigation is to study the Impact Resistance of the Fly ash concrete reinforced with steel fibers. The concrete composite comprises of steel fibers in different percentages and partial replacement of cement in different proportions. Steel fibers varied from 0%, 0.5%, 1% and 1.5% by weight of cement and replacement of fly ash varied from 0%, 10%, 20%, 30% and 40% by weight of cement. Specimens were tested for 28 days, 60 days and 90 days and behaviour of the flyash concrete, steel fiber reinforced concrete and flyash concrete reinforced with steel fibers were studied. When the specimens were tested for 28 days strength, reduction in the Impact strength were observed, while the 90 days strength of the specimens were found to increase considerably. Based on the test results on control specimens, it was found that improvement in strength of concrete is achieved with an optimum steel fiber content of 1.5% and replacement of cement upto 30% by fly ash. The investigation included the possibility of using steel fibers and flyash in concrete for enhancement of impact resistance. The specimens for impact studies were tested by drop weight method which was recommended by ACI-544 Committee. Experiments were conducted to study the behaviour of flyash concrete reinforced with steel fiber. The investigation programme included the determination of the optimum fiber content which can be provided in the concrete composites for different mix ratios. Optimum fiber content was determined based on Impact strength of the standard specimen. The test results reveal that the increase in Impact strength was found to vary between 23% and 252% times the conventional concrete. As the steel fiber percentage selected for our investigation is upto 1.5% by weight, it is suggested that this percentage may be increased to explore the possibility of using more steel fibers in flyash concrete.