FRP-Confined Self-Compacting Concrete under Axial Compression

Abstract

Self-compacting concrete (SCC) has become increasingly popular in recent years, particularly in constructing heavily reinforced concrete structures cast with a stay-in-place form (e.g., concrete-filled tubular columns) where the quality of concrete is difficult to control and/or examine. When used in fiber-reinforced polymer (FRP) tubes, the SCC is subjected to confinement from the FRP tube. While many studies have been conducted on confined normal concrete (NC), research on confined SCC has been very limited. The few existing studies on confined SCC (e.g., steel-confined SCC and FRP-confined SCC) have shown that the behavior of confined SCC may be different from that of confined NC of the same unconfined strength. Against this background, this paper presents the results of a series of axial compression tests conducted to gain a better understanding of the behavior of FRP-confined SCC. The test variables included the concrete strength as well as the type and thickness of the FRP jacket. Similar to FRP-confined NC, the present tests showed that the strength and ductility of SCC can also be significantly enhanced by FRP confinement, and its stress-strain curve also has a bilinear shape. A comparison between the test results and an accurate stress-strain model developed for FRP-confined NC is also presented. The comparison shows that the behavior of FRP-confined SCC is generally similar to that of FRP-confined NC, although the lateral expansion of the former appears to be a little larger.