231 publications from this institution
There is a growing public interest in exploring materials that can enhance the sustainability and durability of conventional steel reinforced concrete (RC) structures, such as geopolymer concrete (GPC) and steel-fibre reinforced polymer composite bars (SFCBs). GPC is produced with industrial waste such as fly ash and slag to replace ordinary Portland cement concrete (OPC), and SFCB is a new reinforcement bar with a layer of fibre reinforced polymer (FRP) enclosing a steel inner core to protect it from corrosion. No studies have ever been reported on the impact-resistant performances of GPC or fibre-reinforced GPC (FRGPC) columns reinforced with SFCBs subjected to vehicle or ship impacts. In this study, GPC/FRGPC columns reinforced with steel-basalt FRP composite bars (SBCBs) were prepared and tested by a pendulum impact testing system. Their impact-resistant performances were compared. It was found that the columns experienced similar damage modes regardless of reinforcement type and fibre content. The addition of hybrid carbon fibres (CFs) and basalt macro fibres (BMFs) could effectively reduce cracking damage and mid height deflections of columns. As compared to steel bar reinforcements, SBCB reinforcements led to similar impact force and maximum mid height deflections, but could reduce the residual mid height deflections of the columns by 7–42% under the impact velocity of 2.64–3.49 m/s, indicating SBCBs have great potential to replace steel bars in constructing more sustainable and durable concrete structures.
During its service life, some reinforced concrete (RC) structures might be subjected to impact loads such as rock fall, vehicle collision, ship impact, and accident dropping of heavy objects.Therefore impact resistance design is essential for the safety and serviceability of such structures.However, the impact behaviour of RC beams is not well understood yet, and methods for strengthening RC structures against impact loading are still very limited.In this study, experimental tests and numerical simulations were conducted to investigate the performance of RC beams with and without fibre reinforced polymer (FRP) strengthening subjected to impact loads.Fourteen rectangular RC beams were experimentally tested under a dropweight test apparatus and intensive numerical simulations are conducted by using LS-Dyna.The impact behaviour of RC beams is observed and compared with its counterpart under static loading.The unique impact response characteristics of RC beams are discussed.It was observed that under impact loadings the equilibrium of the beam was maintained primarily by the inertia resistance of the beam at early stage of the impact process, the contribution from the reaction forces is negligible.The shear failure was found to be critical under impact loads although the identical beam had the shear strength 4 times of the flexural strength and failed in the flexural mode under static loads.The plastic hinge induced by impact load significantly affects the impact behaviour of the RC beams regardless of the boundary conditions in relatively long beams.Strengthening RC beams with FRP can considerably reduce the impact responses in case of the both flexure-and shear-deficient beams.Therefore, strengthening RC beams with FRP is an effective method to improve their performance against impact loading.
