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为了研究钢筋位置对混凝土起裂韧度与失稳韧度等断裂参数的影响,以及钢筋在混凝土裂缝扩展过程中的限裂作用,设计制作了4组在不同位置布置钢筋的三点弯曲试件,对其进行了断裂性能试验研究,并给出了利用叠加原理求解钢筋混凝土试件的起裂韧度与失稳韧度的计算公式。研究结果表明:在加载过程中,钢筋混凝土试件的P-CMOD曲线将出现两个荷载峰值点,其裂缝扩展过程可以用双K断裂判据来描述;起裂韧度与钢筋位置无关,可以作为材料的断裂参数;而失稳韧度受钢筋位置的影响,且钢筋未贯穿裂缝时的失稳韧度远大于钢筋贯穿裂缝时的失稳韧度,这为实际工程中锚杆加固提供了有效的试验依据。
In order to study the influence of the location of rebar on the fracture parameters such as the initial fracture toughness and the instability toughness of concrete and the crack-restraining action of the rebar in the process of concrete crack propagation, four sets of three-point bending test specimens , The fracture performance of the test was studied, and the formulas of calculating the initial fracture toughness and failure toughness of reinforced concrete specimens by using the superposition principle were given. The results show that during the loading process, there will be two peak load points in the P-CMOD curve of the RC specimens, and the fracture propagation process can be described by the double-K fracture criterion. The initiation fracture toughness has nothing to do with the location of the rebars. As the fracture parameter of the material; but the instability toughness is affected by the location of the rebar, and the instability toughness of the rebar when the rebar is not through the fissure is much larger than the instability toughness of the rebar through the fissure, which provides the reinforcement for the actual project Effective test basis.