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对形状记忆合金(SMA)丝采用先张法施加预应力,然后将其作为主筋埋入混凝土中制成SMA混凝土梁。对9个预应变不同的SMA混凝土梁进行自修复性能试验,研究预应变值对SMA混凝土梁自修复性能的影响。对SMA混凝土梁进行三点弯曲试验,然后对SMA丝通电加热观察裂缝变化情况。试验结果表明:预应变越大,梁的承载力越高;预应变为5%~7%时,裂缝的恢复情况较好,当预应变为6%时,裂缝修复率可达到93.8%;当SMA丝的总应变为其最大可恢复应变时,试验梁裂缝的恢复率最高;通过计算荷载作用下SMA丝产生的应变值,可以找到最优的初始预应变值,使修复效果最佳。
The shape memory alloy (SMA) wire is prestressed by the pretensioning method, and then the main reinforcement is embedded into the concrete to make the SMA concrete beam. Nine self-repairing performance tests of nine pre-strained SMA concrete beams were carried out to study the effect of pre-strain on the self-healing properties of SMA concrete beams. The three-point bending test of SMA concrete beam was carried out. Then the SMA wire was heated to observe the change of the crack. The results show that the bigger the pre-strain is, the higher the bearing capacity of the beam is. The recovery of the fracture is better when the pre-strain is 5% ~ 7%, and 93.8% when the pre-strain is 6% When the total strain of SMA wire is its maximum recoverable strain, the recovery rate of cracks in the test beam is the highest. By calculating the strain value of the SMA wire under load, the optimal initial pre-strain value can be found, so that the repair effect is best.