钢纤维和微纤维混合增强混凝土的制备和性能研究

采用钢纤维分别与玄武岩微纤维、聚乙烯醇微纤维、玻璃微纤维混合制备增强混凝土,研究了钢纤维和微纤维混合对混凝土试样的密度、抗压强度、单轴抗拉性能的影响,并分析了混凝土断裂失效机理。结果表明,微纤维的种类不会影响混凝土材料硬化密度。微纤维的长度可以影响混凝土的抗压强度,经过28 d抗压强度测试,发现掺杂玄武岩微纤维、聚乙烯醇微纤维的混凝土抗压强度较基准钢纤维混凝土分别提高了15.4%和14.6%;而掺杂玻璃微纤维的混凝土抗压强度较基准钢纤维混凝土则降低了2.1%。微纤维材料自身的抗拉强度可影响增强混凝土的抗拉性能,掺杂玄武岩微纤维、聚乙烯醇微纤维的混凝土抗拉强度和极限拉伸应变均提高了,而掺杂玻璃微纤维的混凝土却降低了。相比聚乙烯醇微纤维和玻璃微纤维,玄武岩微纤维与钢纤维混合增强混凝土的综合性能最优,其断裂过程中,钢纤维失效方式为纤维拔出,玄武岩微纤维失效方式为纤维断裂。

Preparation and properties of steel fiber and microfiber hybrid reinforced concrete

In this paper, reinforced concrete was prepared by mixing steel fiber with basalt microfiber, polyvinyl alcohol microfiber and glass microfiber. The density, compressive strength and uniaxial tensile properties of concrete samples mixed with steel fiber and microfiber were studied. The impact and analysis of the failure mechanism of concrete fracture were conducted. The results showed that the type of microfiber did not affect the hardening density of concrete materials. The length of microfibers could affect the compressive strength of concrete. After 28 days of test, compressive strength of basalt fiber(SB) and polyvinyl alcohol fiber(SP) concrete were increased by 15. 4% and 14. 6% respectively. Compared with reference ST concrete, compressive strength of glass fiber(SG) concrete was reduced by 2. 1%. The tensile strength of fiber material itself could affect the tensile performance of reinforced concrete, and the tensile strength and ultimate tensile strain of SB and SG concrete were improved. The comprehensive performance of reinforced concrete with mixed basalt fiber and steel fiber was the best. In the process of fracture, the failure mode of steel fiber was pulling out, and the failure mode of basalt fiber was fiber fracture.