Flexural Strength Characteristics of Fly Ash Blended OPC Reinforced Sorrel Fibre Concrete

Abstract

This research work studied the flexural strength characteristics of Fly Ash blended ordinary Portland cement (OPC) concrete reinforced sorrel fibre. This study considered three mix ratios of concrete specimens and were prepared and cast into 100mm × 100mm × 500mm mould of: (1)1:2:4 mix ratio of plain concrete as control sample (2) concrete sample of 1:2:4 mix ratio, reinforced with 1.5% volume fraction of 50mm average length of sorrel fibre (3) Concrete specimens of 1:2:4 mix ratio with binders containing 90% (OPC) + 10% (FA); 80% (OPC) + 20% (FA) and 70% (OPC) + 30% (FA). The water binder ratio was kept constant at 0.6. All the blended samples were reinforced with 1.5% by volume fraction of heat treated sorrel fibre of 50mm average length. The beams specimens were cast for flexural strength tests. The concrete samples were tested in flexure at 7, 28 and 90 days. With the addition of heat treated sorrel fibre, flexural strength increased from 5.0N/mm2, 6.0 N/mm2 and 7.5N/mm2 for optimum blend at 7, 28 and 90days respectively. For the blend containing 10% (FA) + 1.5% volume average length of heat treated sorrel fibre recorded the highest flexural strength mentioned above. The properties of sorrel fibre reinforced concrete was improved with the optimum blend of Fly Ash (FA) and Heat Treated Sorrel Fibre (HSF).