Geogrid-confined pervious geopolymer concrete piles with FRP-PVCconfined concrete core: Concept and behaviour

The use of fibre reinforced polymer (FRP) and polyvinyl chloride (PVC) as strengthening materials for piles was found to be a promising scheme, due to their high strength-to-weight ratio, high durability and high anti-corrosion ability. This study presents an experimental investigation of a new form of composite piles: geogrid-confined pervious geopolymer concrete piles (GPGCPs) with fibre reinforced polymer (FRP)-polyvinyl chloride (PVC)-confined concrete core (FPCC). The GPGCP with FPCC consists of a circular geogrid outer tube, a FRP-PVC-confined normal geopolymer concrete core, and pervious geopolymer concrete (PGC) filled in between. The reason for applying PGC into piles is to increase the rate of consolidation. The aim of using FPCC is to improve the compressive strength and ductility of the concrete. In this study, two groups of GPGCPs (without and with FPCC) were prepared and tested under axial compression. In each group, one layer, two layers, and three layers of geogrid were used to investigate the influence of the outer tube. The test results show that the FPCC can significantly improve the mechanical behaviour of the GPGCPs. In comparison with GPGCPs without FPCC, the maximum axial loads of GPGCPs with FPCC were higher, and the ductility was improved significantly.