Compression Properties of Basalt Fiber–Reinforced Polymer Confined Coconut Shell Concrete

Abstract

The compression property of basalt fiber–reinforced polymer (BFRP) confined coconut shell (CS) concrete (CSC) was examined. The mix ratio of plain concrete as reference was fixed to be 0.60∶1∶1.23∶2.05 for water: cement: sand: stone aggregate by weight, while the stone aggregate was replaced with CS by 25%, 50%, 75%, and 100% in volume. Three groups of BFRP tubes, i.e., 2-, 4-, and 6-layer tubes, with a height of 200 mm and an inner diameter of 100 mm were built. An axial compression test was carried out to examine the strength and deformation capacity enhancement of concrete due to BFRP. Strains in the axial direction and hoop direction, axial force, and failure modes were discussed. Results indicated that the strength of CSC decreased quickly with an increase of the CS replacement ratio. However, with the confinement of the BFRP, the strength and deformation capacities were respectively improved by 1.39–2.65 times and 5.53–9.95 times in comparison with that of the plain concrete. The results also indicate that inclusion of CS changed the failure mode, i.e., BFRP confined plain concrete failed with a vertical crack and BFRP confined CSC was damaged with a horizontal crack.