定向钢纤维增强地质聚合物复合梁的抗弯性能

Flexural Property of Directional Steel Fiber Reinforced Geopolymer Composite Beams

为研究定向钢纤维层厚度对地质聚合物复合梁抗弯性能的影响,制备了不同纤维层厚度的地质聚合物复合梁,并进行了三点弯曲试验.结果表明:复合梁的断裂能随钢纤维层厚度增加而提升,其抗折强度随着钢纤维层厚度的增加呈现先增后减的变化趋势.为深入探讨地质聚合物复合梁钢纤维层厚度与其抗折强度的关系,建立了定向钢纤维增强地质聚合物复合梁受弯承载力简化计算分析模型,通过在模型中引入定向钢纤维增强地质聚合物的抗压强度各向异性测试结果,并以定向钢纤维抗拉强度影响系数(βtu)为变量,对比计算分析了复合梁受弯承载力及界限钢纤维层厚度,发现当βtu≈3时,计算结果与试验结果较为吻合.

To investigate the effect of the thickness of directional steel fiber layer on the flexural behavior of geopolymer composite beam,geopolymer composite beams with different steel fiber layer thicknesses were fabricated and three⁃point bending tests were carried out.The experimental results show that the fracture energy of the composite beam increases as the steel fiber layer thickness increases,whereas the flexural strength increases with the steel fiber layer thickness at the beginning and then descends when the steel fiber layer thickness reaches a certain value.To further explore the reason behind this phenomenon,a simplified bending capacity model is formulated for partial and full sectional steel fiber reinforced geopolymer composite beam,respectively.By introducing the anisotropy of the compressive strength of the directional steel fiber reinforced geopolymer into the model,and taking the influence coefficient(βtu)of directional steel fiber tensile strength as variable,the flexural bending capacity and the optimum thickness of steel fiber layer of composite beam are calculated and analyzed.Whenβtu is about 3,the calculated results are in good agreement with the experimental results.