关键词: 冻融循环, BFRP加固, 力学性能, 复合材料

Abstract: This paper aimed to reduce the effect of freeze-thaw cycles on the mechanical properties of concrete and to extend the service life of freeze-thaw damaged concrete structures in severe cold regions economically and efficiently. In this study, the effect of BFRP cloth reinforcement layers on the bearing capacity of concrete columns with different freeze-thaw damage was systematically investigated through three BFRP cloth wrapping layers (0, 2 and 3 layers) constrained to experience four freeze-thaw cycles (0, 25, 50 and 75 times) for vegetated concrete short columns. The results show that after freeze-thaw cycles, the ultimate bearing capacity of concrete column is significantly reduced and the ultimate displacement is slightly increased. 3 layers of reinforcement increase the ultimate bearing capacity of concrete column by 20%, 16%, 22% and 37% for 0, 25, 50 and 75 freeze-thaw cycles, and also increase the ultimate displacement significantly. From the analysis of the experimental phenomena and data, it was found that additional reinforcement should be applied to the column ends to obtain better reinforcement results. The simulation results of 12 finite element models were established by using ABAQUS and selecting suitable material intrinsic model with reference to the test, and the results were in good agreement with the test results. After considering the effective restrained area division of the FRP-constrained prismatic column, the ultimate stress formula of the BFRP-constrained concrete column and the uniaxial compressive stress principal structure relationship of the freeze-thaw damaged concrete are brought in, and the applicable BFRP-constrained freeze-thaw damaged concrete short column ultimate bearing capacity formula is established.

Key words: freeze-thaw cycle, BFRP reinforcement, mechanical property, composites