纤维超高强混凝土的制备及力学性能试验研究

Preparation of Fiber-reinforced Ultra High-strength Concrete and Experimental Study on its Mechanical Properties

为提高高强、超高强混凝土的韧性和抗开裂性能,采用复合超叠加技术在配制出抗压强度110MPa以上基体混凝土的基础上,分别配制出了钢纤维增强超高强混凝土、PVA纤维增强高强混凝土,同时对不同体积掺量的两种纤维混凝土进行了立方体抗压、轴向抗压、劈裂抗拉、抗弯性能和弹性模量等力学性能的测试,并对超高强纤维混凝土进行了弯曲韧性的试验研究。结果表明,钢纤维对高强混凝土的立方体抗压强度、轴心抗压强度有一定的增强作用,PVA纤维却降低了高强混凝土的立方体抗压强度、轴心抗压强度。两种纤维都能明显改善基体混凝土的劈裂抗拉强度、抗弯强度及弯曲韧性。对此种超高强基体混凝土,钢纤维的增强增韧效果明显好于PVA纤维。

To improve toughness and crack resistance of high-strength and ultra high-strength concrete,based on preparing normal concretes with over 110MPa compressive strength by the multiple super-overlapping technology,steel fiber-reinforced ultra high-strength concrete and PVA fiber-reinforced high-strength concrete are separately prepared.At the same time,the mechanical properties of cubic compressive strength,axial compressive strength,splitting tensile strength,bending behavior and elastic modulus of two kinds of fiber reinforced concrete with different volume dosage are tested.And flexural toughness of ultra high-strength fiber reinforced concrete is researched.The results indicate that cubic compressive strength and axial compressive strength of high strength concrete reinforced by steel fiber have the definite enhancement,but PVA fiber can decrease the cubic compressive strength and axial compressive strength of high strength concrete.Two kinds of fiber can obviously improve splitting tensile strength,bending behavior and flexural toughness of normal concrete.For this kind of ultra high-strength normal concrete,the effects of steel fiber on enhanced intensity and toughness are better than the effects of PVA fiber.