Tensile resistance of a sleeve connector used to connect between two structural components by confining grouted reinforcement bars relies on the bond interaction among reinforcement bars, sleeve and grout. Slippage of the reinforcement bars is customary cause of damage in end-to-end grout-filled reinforcement connector under direct tensile force. In this study, a total of nine specimens with different configuration, in terms of sleeve lengths, sizes, configurations, rebar surface conditions and grouting material, were subjected to tensile test. This paper presents the result obtained from tests conducted on the proposed CS-Series specimens and discusses the failure mode as well as the mechanisms that governed the tensile resistance of the specimens. The test data indicates that threads on reinforcement bar had significantly deteriorated the bonding mechanism between reinforcement bars and grout. None of the specimens could achieve the required strength. However, the understandings of the causes of failures obtained from the study provided essential basis for future research.

High-strength grout is specified to increase the bond between grout and bar in grouted connections and to ensure that the forces in the bars can be transferred to the surrounding material accordingly. Although polymer grout is fast setting and rapid in strength development, the use of polymer mortar in grouted connections is still limited because of the lack of information and familiarity practitioners have regarding the product. The goal of this work is to investigate the mechanical characteristics and performance of polyester grout containing fly ash that can be used as an infill material for grouted connections. This study focused on the composition of polymer grout, which typically consists of a binder, hardener, and filler. In this particular case, the binder was made of unsaturated polyester resin and hardener, while the filler was fine sand. The aim of the research was to investigate the potential benefits of incorporating fly ash as an additional filler in polymer resin grout and examine the mechanical properties of polymer resin grout. To this end, varying amounts of fly ash were added to the mix, ranging from 0% to 32% of the total filler by volume, with a fixed polymer content of 40%. The performance of the resulting grout was evaluated through flowability, compression, and splitting tensile tests. The results of the experiments showed that, at a fly ash volume of 28%, the combination of fine sand and fly ash led to an improvement in grout strength; specifically, at this volume of fly ash, the compressive and tensile strengths increased by 24.7% and 124%, respectively, compared to the control mix. However, beyond a fly ash volume of 28%, the mechanical properties of the grout started to deteriorate. Due its superior properties in terms of compressive and flexural strengths over all examined mixes, the PRG-40-28 mix is ideal for use in the infill material for mechanical connections.

This paper presents experimental results on the influence of the spiral anchor system on the flexural behavior of concrete beams reinforced with glass fiber-reinforced plastic (GFRP) bars. The experimental program consisted of eight beams with the spiral anchor system and two control fiber-reinforced concrete beams without any spiral anchor system. All specimens were tested under bending load. Rough and smooth surface textures of GFRP bars were considered. The test parameters were the diameter of spiral anchor and the condition of the GFRP reinforcement bars as either bonded or unbonded to the surrounding grout. The experimental results indicate that beams reinforced with a rough GFRP bar with an anchor system under flexural load had higher ultimate flexural strength, first crack strength, and stiffness as compared to the beams without an end anchor system. The success of the anchor system is attributed to the confining effect of the steel spiral in anchoring the reinforcement ends. This confining effect enhances the anchorage capacity of the anchor system and subsequently improves the overall flexural performance of the reinforced concrete beams.