引气减水剂对再生混凝土力学性质的影响研究

Investigation on Influence of Air-entrained Water Reduce Agent on Mechanical Properties of Recycle Concrete

把混凝土看作基体,气孔看成夹杂,采用Mori-Tanaka估算方法研究了含气量对混凝土弹性模量的削弱影响规律;基于细观夹杂理论,由变分结构方法导出引气混凝土的有效势能估算式,然后对等效应变求导推出引气混凝土的有效应力-应变关系曲线;最后假定混凝土基体服从D-P屈服准则,通过引入能量密度支函数概念,并构造其函数逼近序列以解决其在气孔边界不可导的问题,最终导出了引气混凝土的宏观D-P屈服准则,并通过它研究了含气量对混凝土内摩擦系数的削弱影响.通过与实验数据的比较,这些力学参数的有效性质随引气量的变化规律基本与实验相吻合.

Taking the concrete as the matrix and the air holes produced in concrete as the inclusions, the decreasing influence of the air content on the Young＇s modulus of the concrete is studied by Mori-Tanaka estimation method. Based on the mesoscopic inclusion theory, the estimation formula of effective potential energy of the air-entrained concrete can be derived by variation structure approach. And then deriving the effective potential energy for equivalent strain, the relation curve between the effective stress and the effective strain for the air-entrained concrete can be derived. Based on the assumption of the D-P yield criterion of concrete matrix, the macroscopic D-P yield criterion of air-entrained concrete is derived finally by introducing the energy density supporting function and constructing the approximating function sequence to solve the non-derivable problem on the boundary of the air hole finally for energy density supporting function. The decreasing influence of the air content on the inner friction coefficient of concrete is studied. Compared with the experiment data, the variance characteristics of the effective properties of these mechanical parameters with the variance of the air content is found to match the experiment case approximately.