纳米改性再生骨料混凝土破坏机理研究

发布时间：2018-01-18 10:31

本文关键词：纳米改性再生骨料混凝土破坏机理研究　出处：《建筑材料学报》2017年05期 　论文类型：期刊论文

【摘要】：对再生骨料混凝土(RAC)进行了裂纹演变规律和不同掺量的纳米硅溶胶、纳米碳酸钙改性试验研究.采用高速摄像仪实时观测了不同水灰比(mW/mC=0.4,0.5和0.6)和不同再生骨料替代率下再生骨料混凝土试块单轴受压加载过程中的裂纹开展信息,对不同纳米材料改性的RAC进行了扫描电镜和压汞测试,并对其界面过渡区的微观形貌和孔结构进行了对比分析.结果表明:RAC的受压破坏大多为新老界面过渡区破坏,裂纹往往最先由此处开展,具体开裂位置取决于新老砂浆的相对强度;裂纹围绕再生骨料周边逐步向四周扩展和贯通,最终导致试块纵向劈裂破坏;纳米硅溶胶能够很好地改善RAC界面过渡区微观结构,提高RAC抗压强度,而纳米碳酸钙难以进入RAC的界面过渡区,很难有效改善界面孔结构,因此未能明显提高RAC抗压强度.
[Abstract]:The crack evolution of recycled aggregate concrete (RC) and nano-silica sol with different contents were studied. Experimental study on the modification of nanometer calcium carbonate. The different water / cement ratio (MW / mCU) 0.4 was observed in real time with a high speed camera. 0.5 and 0.6) and the crack development information of recycled aggregate concrete under uniaxial compressive loading under different recycled aggregate substitution rates. The RAC modified by different nano-materials was tested by scanning electron microscope and mercury injection. The microscopic morphology and pore structure of the transition zone of the interface are compared and analyzed. The results show that the compressive failure of the W RAC is mostly the failure of the transition zone of the new and old interfaces, and the crack is usually carried out here first. The specific cracking position depends on the relative strength of the new and old mortar. The crack around the regenerated aggregate expands and penetrates gradually, which leads to the longitudinal splitting failure of the specimen. Nano-silica sol can improve the microstructure of RAC interface transition zone and increase the compressive strength of RAC, while nano-calcium carbonate can not enter the interface transition zone of RAC, and it is difficult to improve the interface pore structure. Therefore, the compressive strength of RAC can not be improved obviously.
【作者单位】：湖南大学土木工程学院;悉尼科技大学(UTS)土木与环境工程学院;
【基金】：国家自然科学基金资助项目(51408210) 中央高校基本科研业务费专项资金项目(531107040800)
【分类号】：TU528
【正文快照】： 2.悉尼科技大学(UTS)土木与环境工程学院,新南威尔士悉尼2007)再生骨料混凝土(RAC)能在很大程度上减少建筑垃圾,实现混凝土的循环利用,因此对于RAC的研究成了混凝土领域的热点.针对RAC的性能缺陷[1-2],许多学者对影响因素及如何提高其抗压强度进行了相应研究,其中肖建庄等[3]

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