Mechanical properties of glass fibre reinforced concrete with palm oil fuel ash

Abstract

In the absence of steel reinforcement, the brittle nature of conventional concrete always results in catastrophic failure without warning. Researches since decades ago shown that the addition of fibres into the concrete enhanced its ductility while admixtures help to strengthen the cement matrix. To study the effects of palm oil fuel ash (POFA) on the mechanical properties of glass fibre reinforced concrete (GFRC), an experimental programme involved Vebe consistency test, ultrasonic pulse velocity test, compressive strength test, splitting tensile strength test and flexural strength test was carried out. Normal concrete and GFRC with 0, 10, 20 and 30% of POFA were prepared and tested at the age of 1, 7, 28 and 90 days. The glass fibre used was 12mm Cem-Fil Alkali-Resistant (AR) glass fibre added into the concrete at a percentage of 0.5 by volume of concrete. The result shows that the addition of glass fibres reduced the workability of the concrete but the use of superplasticiser helped to compensate the loss. In term of mechanical properties, glass fibres reduced the compressive strength of the concrete for about 10.0% but 20% replacement of cement with POFA gave a 5.4% improvement to the compressive strength at later age. With the incorporation of glass fibres into the concrete, the splitting tensile strength and flexural strength were increased by 2.2% and 20.0% respectively. The replacement of 20% cement with POFA further enhance the concrete for another 8.2% and 10.6% of splitting tensile and flexural strength respectively. In conclusion, glass fibres reduced the compressive strength of the concrete but it helped in improving the splitting tensile and flexural strength of the concrete. To strengthen the concrete, 20% replacement of cement with POFA was found to be the optimum value.