钢筋钢纤维自密实混凝土梁裂缝宽度试验研究

EXPERIMENTAL RESEARCH ON CRACK WIDTH OF STEEL FIBERS REINFORCED SELF-CONSOLIDATING CONCRETE BEAMS

通过9根钢筋钢纤维自密实混凝土梁的四点弯曲试验,分析了钢纤维体积率、配筋率对钢筋钢纤维自密实混凝土梁裂缝形态、裂缝宽度以及裂缝间距等参数的影响。结果表明:在自密实混凝土梁中掺加钢纤维可有效限制裂缝的扩展,掺入体积率为0.38%和0.64%的钢纤维,可使自密实混凝土梁在正常使用阶段的最大裂缝宽度减小31%~56%,平均裂缝间距减小15%~28%,纵筋应变减小40%~56%。考虑钢纤维在试验梁开裂截面的分布以及应力传递机理,结合试验数据提出了钢筋钢纤维自密实混凝土梁最大裂缝宽度的计算公式,并与MC2010、RILEM TC-162 TDF及CECS 38:2004的公式进行了对比。计算结果表明:该文建议公式计算的最大裂缝宽度与试验值吻合较好,可用于钢筋钢纤维自密实混凝土梁最大裂缝宽度的分析与验算。

Based on a four-point bending test of nine steel fiber reinforced self-consolidating concrete（SFRSCC） beams, the influencing factors, such as the volume fraction of steel fibers and reinforcement ratio, on the crack pattern, crack width and crack spacing were investigated. The results showed that adding steel fiber into reinforced SCC beams could restrict the crack development effectively. With 0.38% and 0.64% steel fiber by volume, the maximum crack width of the SFRSCC beam was decreased by 31% - 56%, the mean crack spacing was decreased by 15% - 28%, and the strain in steel bar was decreased by 40% - 56%. Finally, considering the fiber distribution across the cracks and the stress transfer mechanism of steel fiber, the maximum crack width calculation method of SFRSCC beams was proposed. Compared with the methods of MC 2010、RILEM TC-162 TDF and CECS 38： 2004, the proposed method fit better with the test results. Thus, the proposed formula of maximum crack width can be used for the analysis and design of steel fiber reinforced SCC beam.