再生混凝土梁长期受荷时随变形计算方法研究

由于再生混凝土收缩徐变效应大，导致长期荷载作用下，再生混凝土梁附加变形较大。文中以不同再生粗骨料取代率的再生混凝土梁长期受荷变形性能的试验研究为依据，研究其长期变形计算方法。通过考虑龄期的有效弹性模量法，将再生混凝土徐变系数引入梁截面附加曲率的计算，基于虚功原理给出长期荷载作用的时随变形计算公式|考虑再生粗骨料的二相性，通过普通混凝土的徐变收缩计算式，给出考虑附着水泥砂浆影响的再生混凝土徐变收缩调整系数|将其计算结果代入三种典型普通混凝土徐变收缩模型，得到再生混凝土徐变收缩模型，并通过时随变形计算公式计算再生混凝土梁长期荷载下的跨中变形值、跨中和加载点的附加变形值，与试验结果吻合较好。

Time-dependent calculation method for the long-term deformation of recycled aggregate concrete beams

Under the long duration load, the recycled aggregate concrete beams may suffer substantial additional deformation due to the shrinkage and creep effect of recycled aggregate concrete. Based on the long duration load experiments of recycled aggregate concrete beams with different replacement ratios of recycled aggregate, the time-dependent calculation method for the long duration deformation was studied. According to the virtual work principle, the computational formula for long-term deformation, in which the effective elastic modulus method with age of concrete considered was employed and the creep factor of recycled concrete was introduced into the calculation of additional curvature of beam section, was given. Based on the calculation formula of creep and shrinkage for ordinary concrete, the creep and shrinkage adjustment coefficients of recycled concrete with the effect of adhering cement mortar considered were provided. By substituting the calculation results into three typical creep and shrinkage models of ordinary concrete, the creep and shrinkage model for recycled concrete was derived. It was found that based on the proposed formula, the calculated mid-span deformation, the additional deformations at mid-span and loading point agreed well with the experimental results.