High-temperature performance of coconut fibre-reinforced coral concrete

Coconut fibre is low carbon and environmentally friendly and has a low cost, relatively high strength and toughness, and can be incorporated into concrete to improve the latter's resistance to high-temperature bursting. In this study, an appropriate amount of coconut fibre was added to coral concrete to simultaneously solve the problems of low early strength, large shrinkage and poor resistance to high-temperature bursting of coral concrete and to initially establish the theoretical system of coconut fibre-reinforced coral concrete (CF-CC) to lay a theoretical foundation for solving the intrinsic defects of coral concrete and expanding its engineering applications. The results show that there is no obvious cracking in the specimen above 700oC.At 900oC, many cracks penetrated the specimen. At 20–100oC, the specimen mass loss was very low. At 300oC, the specimen mass loss rate was approximately 9%. Afterwards, the change in mass loss rate with temperature was relatively small. The compressive strength peaked at 100oC, with a maximum increase of nearly 10%, and decreased considerably at 300oC, with a maximum decrease of 16.5%. At 500oC, the average compressive strength decreased by approximately 10%. The compressive strength–temperature curve tended to stabilise. At 20oC, the addition of coconut fibres with densities of 3–4.5 kg/m3 considerably enhanced the tensile strength, with a maximum increase of approximately 20%. Then, at 100oC, the addition of coconut fibre slightly increased the coral concrete tensile strength, with a maximum increase of 7.5%. Above 100oC, coconut fibre minimally affected the coral concrete tensile strength.