再生混凝土徐变试验及机理的模型化分析

Experiment and Mechanism Modeling Analysis on Creep of Recycled Aggregate Concrete

通过改变再生粗骨料取代率,对再生混凝土的立方体抗压强度、棱柱体抗压强度、弹性模量等力学性能和收缩徐变性能进行了试验。在试验研究的基础上,通过将再生混凝土模型化为单骨料平面模型,建立了再生混凝土徐变的有限元计算模型,利用ANSYS软件分析了单轴受压时模型化再生混凝土的徐变发展特点,揭示了再生混凝土徐变的机理。研究结果表明:再生混凝土的28d立方体抗压强度和弹性模量随再生粗骨料取代率的增加而降低,再生混凝土的收缩和徐变随再生粗骨料取代率的增加而增加;模型化再生混凝土中由于受到新砂浆、老砂浆徐变的影响,随着时间的推移,砂浆应力将向粗骨料转移;利用ANSYS软件计算所得模型化再生混凝土徐变和试验数据基本吻合。

The experiment on creep and mechanical properties of recycled aggregate concrete （RAC） was conducted by varying the reeyeled coarse aggregate （RCA） replacement percentage. Based on the experiment study, a finite element model was established to analyze the creep mechanism by modeling the reeycled concrete as a plane model with one aggregate. The creep of modeled RAC under uniaxial compression was simulated by ANSYS software. The study results show that the 28 d cube eompressive strength and elastic moduli of RAC are reduced whereas the shrinkage and creep of RAC increase with the increase of RCA replacement percentage. The simulation results reveal that the stress of new mortar and old mortar will transfer to the coarse aggregate due to the creep of mortar. The creep of modeled RAC by ANSYS software is consistent well with the experiment result.