程 俊1,刘加平1,张丽辉2
超高性能混凝土纤维-基体黏结性能测试与机理分析
程 俊1,刘加平1,张丽辉2
摘 要:为研究超高性能混凝土纤维-基体黏结性能,通过单根纤维拉拔试验得到纤维拔出应力-位移曲线,并研究界面参数对纤维黏结性能的影响;通过扫描电镜观察、比较拔出纤维表面和端部形貌,发现钢纤维被拔出后,端部和表面黏结大量“球状”碎屑,且表面有“切削”痕迹,当钢纤维体积掺量为2%、埋入深度为3mm时,拔出纤维表面附着的碎屑密度最大,纤维-基体黏结强度最佳;结合混凝土拉伸本构模型,计算理论拉伸强度σc1,并通过配制相应的混凝土,利用单轴拉伸试验测得试验拉伸强度σc2,比较发现,其误差范围为5%±2%。
Abstract: In order to study bonding properties of fiber-matrix adhesion of ultra-high performance concrete, a stress-displacement curve is obtained by a single fiber pullout experiment, and the influence of interface parameters on fiber bonding properties is investigated; the surface and end of steal fiber attach to large numbers of "spherical" clastic by scanning electron microscopy and the surface has "cutting signs" at the scene, when the volume content of fiber is 2%, buried depth reaches 3mm, density of "spherical" clastic attached to the surface of pulled fiber is the largest, bonding properties of fiber-matrix is the best; combining stretch constitutive model of concrete, calculating the theoretical tensile strength σc1 and formulating the corresponding concrete, measuring the tensile strength σc2 by uniaxial tensile test, which the error range is 5%±2%.
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