Durability of polyester-based GFRP subjected to hybrid environmental and mechanical loads

Abstract

Fiber reinforced polymer (FRP), as a new alternative construction material compared to conventional materials like concrete and steel, has been introduced into civil infrastructure area for centuries and gained increasing interests by many researchers and contractors. FRP exbits several property advantages, such as high strength-to-mass ratio, ease of handling, and relatively high resistance to corrosion. However, one problem that hinders this material from wider acception in civil infrastructure application is the durability of FRP subjected to harsh complicated environmental conditions has not been fully investigated yet. This paper is aim to study the performance of the polyester-based glass fiber reinforced polymer (GFRP) subjected to combined cement alkaline solution, freeze-thaw cycles, wet-dry cycles, heating-cooling cycles, and sustained mechnical load. Concrete was poured into GFRP tube to make concrete-filled FRP tube (CFFT) cylinders, and the cylinders were put into environmental chamber with sustained axial load on. The concrete core of the CFFT cylinders was removed after 72-day’s conditioning, and the outer GFRP tube was cut into ring specimens to conduct hoop tensile tests. Test results indicated that the conditioned GFRP was slightly degraded in strength, but had significant decrease in strain. Sustained load had negligible effect on the strength of GFRP specimens, but did further deteriorate the strain of loaded specimens compared to unloaded specimens.