Bond between glass fibre reinforced polymer bars and high - strength concrete

Abstract

In this study, bond properties of glass fibre reinforced polymer (GFRP) bars embedded in high-strength concrete (HSC) were experimentally investigated using a pull-out test. The experimental program consisted of testing 84 pull-out specimens prepared according to ACI 440.3R-12 standard. The testing of the specimens was carried out considering bar diameter (9.5, 12.7 and 15.9 mm), embedment length (2.5, 5, 7.5 and 10 times bar diameter) and surface configuration (helical wrapping with slight sand coating (HW-SC) and sand coating (SC)) as the main parameters. Twelve pull-out specimens reinforced with 16 mm steel bar were also tested for comparison purposes. Most of the specimens failed by a pull-out mode. Visual inspection of the tested specimens reinforced with GFRP (HW-SC) bars showed that the pull-out failure was due to the damage of outer bar surface, whilst the detachment of the sand coating was responsible for the bond failure of GFRP (SC) reinforced specimens. The bond stressslip behaviour of GFRP (HW-SC) bars is different from that of GFRP (SC) bars and it was also found that GFRP (SC) bars gave a better bond performance than GFRP (HW-SC) bars. It was observed that the reduction rate of bond strength of both GFRP types with increasing the bar diameter and the embedment length was reduced in the case of high-strength concrete. Bond strength predictions obtained from ACI-440.1R, CSA-S806, CSA-S6 and 2 JSCE design codes were compared with the experimental results. Overall, all design guidelines were conservative in predicting bond strength of both GFRP bars in HSC and ACI predictions were closer to the tested results than other codes.

Bond Behavior of GFRP-Concrete Under Long-term Exposure to Aggressive Environments

“…2(a), the GFRP bar was embedded in the center of the cubic concrete, and the length of its bonded section was set as 60 mm according to the Chinese Standard, being a little more than 5 times of the nominal bar diameter. Based on former studies, the bond strength might be decreased along with the increasing of embedment length (Saleh et al 2019;Achillides and Pilakoutas 2004). This is possibly owing to the influence from the non-uniformly distributed bonding stress along the embedment length, and the decreasing of bar dimension caused by the Poisson effect, which further reduce the mechanical bonding resistance (Huang et al 2020).…”

Bond durability between anchored GFRP bar and seawater concrete under offshore environmental conditions

“…Although numerous studies have been conducted to study the bond performance of various concrete and FRP bars [31,[40][41][42], most of them have concentrated on short-term performance [43]. Indeed, some researchers have examined the durability of the bond between concrete and FRP bars subjected to various conditions, including seawater [44][45][46][47][48].…”