聚丙烯纤维混凝土直接拉伸性能的试验研究

重点研究聚丙烯纤维增强混凝土在单轴直接拉伸荷载下的力学性能和纤维混凝土的单轴拉伸应力变形全曲线。提出单轴拉伸相对应力裂缝宽度曲线的理论方程式。由单轴拉伸全曲线得到了纤维混凝土的应力裂缝宽度曲线、断裂能及特征长度等。试验发现:当纤维体积掺量为0 14%时,纤维混凝土的轴心抗拉强度比基准混凝土提高20%,极限拉伸应变提高49%,断裂能提高68%,临界断裂时的最大裂缝宽度增加55%。聚丙烯纤维具有良好的阻裂性能,增强了硬化混凝土的能量吸收能力。

The Uniaxial Tension Test of Polypropylene Fiber Reinforced Concrete

Uniaxial tension test of polypropylene fiber reinforced concrete was presented in this paper.The complete stress-strain responses in tension were acquired through a systematic experimental program. Theoretical models for normalized axial stress versus normalized maximum crack width curve in unixial tension were proposed. The axial stress-crack width curves, fracture energy and brittleness of concrete with fiber were also obtained based on the complete stress-deformation curves. It was found that the tensile strengths of fiber reinforced concrete is about 20% higher than that of benchmark concrete when fiber volume fraction is 0.14% with extreme strain increased by 49%,the fracture energy in creased by 68% and maximum crack width in creased by about 55%.Polypropylene fiber reinforced concrete possesses good ductility and energy absorbability.