基于图像重建的大粒径再生粗骨料混凝土单轴受压性能研究

Mechanical analysis on uniaxial compression behavior of concrete with large-size recycled coarse aggregate based on image reconstruction model

针对粒径为25~80 mm的大粒径再生粗骨料混凝土,基于图像重建方法,采用ANSYS有限元软件建立数值模型对其立方体单轴受压性能进行了研究。模拟结果表明:再生粗骨料的形状对再生混凝土中裂缝萌生有影响,初始裂缝出现在再生粗骨料的棱角处;再生混凝土中裂缝发展初期,主要沿新老砂浆界面和天然石子与新砂浆界面发展,然后向新砂浆和老砂浆内部延伸;新混凝土强度低于老混凝土强度时,大粒径再生粗骨料混凝土试件破坏相对较轻;大粒径再生粗骨料混凝土试件中新老砂浆界面对强度有较大影响,该区域在试件破坏前后都是应力最大的区域。

Based on the image reconstruction model, the uniaxial compression behavior of concrete with 25~80 mm large-size recycled coarse aggregate (LRCA) was numerically studied using finite element method (FEM) software ANSYS. The simulation results reveal the following conclusions: the shape of recycled aggregate has influence on the crack initiation and the initial cracks occurr at corners of recycled aggregates; in the early stage of crack growth in concrete, the major cracking is developed along the interface between old mortar and new mortar and the interface between gravel and new mortar, then cracking extends to the old mortar and new mortar, and the recycled coarse aggregate is cracked later; when the new concrete strength is lower than old concrete strength, the damage is relatively mild; the interface between old and new mortar in LRCA specimen has a greater effect on the strength, and the stress in these zones is the largest before and after the breaking of RAC specimen. © 2016, Editorial Office of Journal of Building Structures. All right reserved.