碳纤维混凝土单轴受压应力-应变本构关系

Study on Uniaxial Compression Stress-strain Constitutive Relation of Carbon Fiber Reinforced Concrete

碳纤维混凝土受压应力-应变全曲线研究是对其基本力学性能进行全面认识的基础,也是表现碳纤维混凝土基本受压特性的综合宏观反映。对9组(碳纤维体积分数分别为0,0.2%,0.4%,0.6%,0.8%,1.0%,1.2%,1.4%,1.6%)碳纤维混凝土试件进行了立方体和棱柱体抗压强度试验,结果表明碳纤维混凝土立方体和棱柱体抗压强度随碳纤维体积分数的增加呈下降趋势,峰值应变随碳纤维体积分数的增加呈增大趋势。基于各体积分数碳纤维混凝土的棱柱体抗压强度和峰值应变的试验数据,拟合得到了棱柱体抗压强度和峰值应变与体积分数之间的函数表达式。利用微机控制电液伺服压力试验机测定了9组碳纤维混凝土应力-应变全曲线,参照非线弹性理论的混凝土单轴受压应力-应变本构模型,根据测得的全曲线应力-应变数据,拟合得到了应力-应变全曲线上升段表达式参数和下降段表达式参数,最后给出了基于碳纤维体积分数变化的碳纤维混凝土单轴受压应力-应变本构方程。

The research of carbon fiber reinforced concrete compressive stress-strain curve is the basis of a comprehensive understanding of its basic mechanical properties, and also a comprehensive macro reflection of carbon fiber reinforced concrete compression characteristics. Nine volume percentages （0,0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6% ）of carbon fiber reinforced concrete have been tested for the cube and prism compressive strengths. The test result shows that the compressive strengths of carbon fiber reinforced concrete in cube and prism decrease with the volume percentage increasing and the peak strains of the concrete tend to increase with the volume percentage increasing. By fitting test data on the basis of the data from the compressive strength and peak strain of the prism of carbon fiber reinforced concrete, this paper achieves the function expression of relationship between compressive strength and volume percentage, and that between peak strain and volume percentage. And nine volume percentages of carbon fiber reinforced concrete are tested by using the microcomputer controling servo pressure machine to get stress-strain curves.With reference to the non-linear theory of elasticity of concrete under uniaxial compression stress-strain constitutive model and based on the stress-strain data, this paper gets the stress-strain curve of rising segment expression parameter and that of descent stage expression parameter by data fitting, and it proposes uniaxial compressive stress-strain constitutive equation of carbon fiber reinforced concrete based on the variation of volume percentage of carbon fiber.