包浆再生骨料混凝土力学与收缩性能试验研究

基于建筑废弃物资源化利用的发展理念,制备了包浆再生骨料混凝土,试验研究了应用不同处理方法的再生骨料对该混凝土材料的抗折强度、抗压强度和收缩性能的影响规律,建立了收缩模型,并运用秩和检验方法检验了其显著性;采用扫描电镜图像分析(SEM)研究了混凝土界面过渡区的结构。试验结果表明:包裹用水泥浆中胶粉和硅粉协同作用可以明显改善包浆再生骨料混凝土界面过渡区的结构,提高抗压强度和抗折强度;再生骨料包浆3 d拌制的混凝土强度较高,收缩最大,包浆28 d拌制使得混凝土收缩最小;硅粉对包浆再生骨料混凝土35 d之前的收缩抑制效应明显,35 d之后胶粉抑制效应显著;包浆再生骨料混凝土收缩率与龄期满足指数函数关系,且在水平α=0.01下其相关关系显著。

Experimental study about mechanical and shrinkage properties of wrapped paste recycled aggregate concrete

Based on the development concept of the utilization of construction waste resources,the wrapped pasted recycled aggregate concrete was prepared.The effects of recycled aggregates with different treatment methods on the flexural strength,compressive strength and shrinkage performance of the concrete were studied.The shrinkage model was established and its significance was tested by the rank sum test method.The structure of the transition zone of concrete interface was studied by scanning electron microscopy image analysis(SEM).The test results show that the synergistic effect of rubber powder and silica powder in the cement slurry can significantly improve the structure of the transition zone of the wrapped paste recycled aggregate concrete,improve the compressive strength and flexural strength.The strength and shrinkage of the concrete mixed with the aggregate for 3 d is higher while the 28 d mixing of the pulp makes the shrinkage minimum.The shrinkage inhibition effect of the silica powder on the recycled aggregate concrete is obvious before the 35 d,and the inhibition effect of the rubber powder is significant after 35 d.The shrinkage ratio and the age meets the exponential function,and the correlation is significant at the levelα=0.01.