周长伟,高丹盈,赵亮平
纤维纳米混凝土劈拉性能试验研究
周长伟,高丹盈,赵亮平
摘 要:通过劈拉试验,测定了20组纤维纳米混凝土试块的劈拉强度和劈拉荷载-横向变形曲线,探讨了钢纤维掺量及类型、纳米矿粉种类及掺量、混凝土强度对纤维纳米混凝土劈拉性能的影响。结果表明:随钢纤维掺量增加,纤维纳米混凝土劈拉性能明显提高;端钩型纤维更能有效地提高纤维纳米混凝土的劈拉性能,约束横向变形;随纳米SiO2掺量增加,劈拉强度先升高后降低,韧性变化不显著;随纳米CaCO3掺量增加,劈拉强度先升高后降低,韧性大致呈增长趋势;较高的混凝土基体强度有利于劈拉性能的提高;掺入适量的纤维和纳米矿粉,改善了混凝土的微细观结构,提高了混凝土自身的密实度,有效提高了混凝土的劈拉性能。
Abstract: Based on the splitting tensile tests,the splitting tensile strength and splitting tensile load-transverse deformation curve of 20 sets fiber and nanometer materials reinforced concrete(FNMRC)samples were studied. The effects of steel fiber content and its type, nanometer material type and its content, and concrete matrix strength on the splitting tensile properties of FNMRC were investigated. The results show that: the splitting tensile properties of FNMRC increases obviously with the increasing steel fiber content; the end-hooked steel fiber can improve the splitting tensile properties of FNMRC and restraint transverse deformation more effectively; with the increasing replacement rate of cement by nanometer SiO2, the splitting tensile strength first increases and then decreases, but there is no significant change in the splitting tensile toughness; with the increasing replacement rate of cement by nanometer CaCO3,the splitting tensile strength first increases and then decreases, the splitting tensile toughness increased gradually; higher concrete matrix strength is beneficial to improving the splitting tensile properties; by adding right content of steel fiber and nanometer materials into the concrete, the microstructure, compactness and the splitting tensile properties of FNMRC are all improved.
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