短期荷载作用下再生骨料混凝土梁正截面裂缝宽度试验研究

Experimental research on crack widths of normal sections of recycled aggregate concrete beams under short term loading

通过27根再生骨料混凝土梁和3根普通混凝土梁的正截面弯曲试验,比较了再生骨料混凝土梁与普通混凝土梁的正截面裂缝宽度。研究结果表明:再生骨料混凝土梁的裂缝发展比普通混凝土梁更复杂,较多出现裂缝的中断、汇合和分叉等现象;再生骨料混凝土梁裂缝间距比普通混凝土梁小;随着钢筋直径和配筋率比值的减小及保护层厚度的减小,再生骨料混凝土梁的裂缝宽度减小;再生骨料混凝土梁最大裂缝宽度的离散性和普通混凝土梁相近。根据试验结果,回归出短期荷载作用下再生骨料混凝土梁最大裂缝宽度的表达式,该计算式与其他研究者的试验结果吻合较好。

Based on bending experiment of twenty-seven recycled concrete beams and three normal concrete beams,the difference in crack widths between recycled concrete beams and normal concrete beams was compared in this paper.The results show that the cracking pattern of recycled concrete beams is more complicated and random than that of normal concrete beams.The branching and converging of cracks of recycled aggregate concrete beams are more apt to occur than normal concrete beams.The crack widths of recycled concrete beams are smaller than those of normal concrete beams,and the crack widths can be reduced when the ratio of the rebar diameter to the percentage of reinforcement and the thickness of cover decrease.The randomness of crack widths of recycled concrete beams is similar to that of normal concrete beams.The expression of flexural crack width of reinforced concrete beams with recycled coarse aggregates under short term loading is presented as the result of experiments.The calculated values of crack width of recycled aggregate beams are in good agreement with the test values obtained by other researchers.