硫酸盐腐蚀后混凝土单轴受压本构关系

为了研究硫酸盐侵蚀环境下混凝土力学性能的变化,对受硫酸盐腐蚀的普通混凝土进行单轴受压实验.通过实验室加速腐蚀的实验方法,测定不同腐蚀时期的混凝土的应力应变全曲线,研究受腐蚀混凝土应力-应变曲线上的几个特征值(峰值应力及应变、弹性模量、割线模量、拐点应力及应变、收敛点应力及应变)随腐蚀程度变化的规律,对腐蚀后混凝土的应力应变全曲线进行拟合.结果表明:随腐蚀的进行,混凝土峰值应力、弹性模量先增加后减小,而峰值应变是先稍微有所减小,而后急剧增大;该实验条件下获得了受腐蚀后混凝土应力应变曲线上各特征值与峰值应力fc′的关系式,建立了曲线上升段参数αa的数学表达式.可以以受腐蚀混凝土的强度为基本参数,分别求解受腐蚀混凝土峰值应变、弹性模量,上升段曲线拟合参数、拐点应力以及收敛点应力.从而得到受腐蚀混凝土一系列的力学参数和本构关系.

Constitutive relation of sulfate attacked concrete under uniaxial compression

In order to study the mechanics performance change of the concrete attacked by sulfate,uniaxial compression experiments of concrete with different sulfate corrosion degrees were conducted by the accelerated deterioration experiment technique,and the full stress-strain curves were measured.By analyzing the staged characteristics of the full stress-strain curves,the regularity of the strength,strain and modulus of sulfate attacked concrete was discussed.Meanwhile,the full stress-strain curves were fitted with the equation suggested in the structure design code.The results show that the strength and the modulus first increase and then decrease,while as the strain is decreased and then increased with the corrosion progressing.The formulation of the coefficient(αa)of the curves was derived through regression analysis.Thus a series of mechanics parameters and constitutive relation of sulfate attacked concrete under uniaxial compression can be obtained.