蒸养GFRP筋钢纤维再生混凝土梁受弯性能研究

Research on bending performance of steam-cured GFRP reinforced steel fiber recycled concrete beam

为提高废弃混凝土利用率,以及解决钢筋容易腐蚀的问题,同时能将蒸养的优势运用到工程中来,研究了不同体积率的钢纤维对蒸养GFRP筋钢纤维再生混凝土梁受弯性能的影响,本试验制作了4根试验梁分析其裂缝形态、开裂荷载、极限荷载、荷载-挠度曲线、平截面假定、受拉钢筋应变。同时制作了8个再生混凝土立方体试块测其抗压强度、观测其破坏形态。试验结果表明:钢纤维可提高再生混凝土抗压强度,且以钢纤维体积率为1.0%时最优,钢纤维可改善再生混凝土的脆性;钢纤维体积率越大,试验梁的开裂荷载和极限荷载提高越明显;4种GFRP筋钢纤维再生混凝土梁的破坏方式均为正截面受弯破坏并符合平截面假定;钢纤维能提高试验梁的抗裂能力并降低试验梁挠度及受拉钢筋应变。

In order to improve the utilization rate of waste concrete and solve the problem of easy corrosion of steel bars, at the same time, the advantages of steam-curing can be applied in the project, the influence of steel fibers with different volume fractions on the bending performance of steam-cured GFRP reinforced steel fiber recycled concrete beams was studied. In this experiment, four test beams were set up to analyze the crack shape, cracking load and ultimate load, load-deflection curve, flat section assumption and strain of tensile steel bar. At the same time, 8 recycled concrete cube test blocks were made to measure their compressive strength and observe their failure modes. The test results show that: steel fiber can increase the compressive strength of recycled concrete, and the optimal volume rate of steel fiber is 1.0%. Steel fiber can improve the brittleness of recycled concrete;the larger the volume rate of steel fiber, the more obvious the increase of the cracking load and ultimate load of the test beam;the failure modes of the four GFRP steel fiber recycled concrete beams are all normal section bending failure and conform to the flat section assumption;steel fiber can improve the crack resistance of the test beam and reduce the deflection of the test beams and the strain of the tensile steel bars.