剑麻纤维自密实轻骨料混凝土梁裂缝宽度试验研究

Experimental Study on Crack Width of Sisal Fiber Self-compacting Lightweight Aggregate Concrete Beams

通过对强度等级为C40的剑麻纤维自密实轻骨料混凝土梁进行抗弯性能试验,研究了剑麻纤维的掺量和配筋率对自密实轻骨料混凝土梁的裂缝形态、裂缝间距和裂缝宽度的影响,通过最大裂缝宽度计算公式进行了理论分析。试验结果表明,与未掺加纤维的混凝土试块和试验梁相比,剑麻纤维掺量为1 kg/m^3、2 kg/m^3和3 kg/m^3时混凝土试块的劈裂抗拉强度提高6.57%、23.87%、31.49%,试验梁的开裂荷载提高了0、12.5%和35%;掺加剑麻纤维可有效限制裂缝的产生和发展,并改善裂缝形态,与未掺剑麻纤维的试验梁相比,掺加1 kg/m^3、2 kg/m^3和3 kg/m^3的剑麻纤维可使自密实轻骨料混凝土梁最大裂缝宽度减小5%、12%和27%。

The bending performance of C40 self-compacting lightweight aggregate concrete beams with sisal fiber are tested, and the amount of sisal fiber and the ratio of reinforcement to the crack morphology and crack spacing of self- compacting lightweight aggregate concrete beams are investigated. And the effect of crack width is studied by the theoretical analysis of the maximum crack width calculation formula. The test results show that the splitting tensile strength of the test piece is increased by 6.57%, 23.87% and 31.49% when the sisal content is 1 kg/m3, 2 kg/m3 and 3 kg/m3, compared with the test piece without the fiber and the test beam. The cracking load of the test beam is increased by 0, 12.5% and 35%; the addition of sisal fiber can effectively limit the generation and development of cracks and improve the crack morphology, compared with the test beam without sisal fiber. The maximum crack width of self-compacting lightweight aggregate concrete beams can be reduced by 5%, 12%, and 27% for sisal fibers with contents of 1 kg/m3, 2 kg/m3 and 3 kg/m3.