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分别制作相同配合比的再生粗集料混凝土和普通混凝土试件.在养护龄期为3,7,14,28d时,将再生粗集料混凝土试件切割,取样,然后对其内部不同界面微观结构进行扫描电镜观测;同时对再生粗集料混凝土和普通混凝土试件进行了抗压强度试验,观察了加载后再生粗集料混凝土试件内部裂纹的分布情况.结果表明:随着龄期的增长,再生粗集料混凝土各个界面过渡区都有不同程度的发展;天然粗集料新砂浆界面过渡区发展相对缓慢;再生粗集料中老砂浆新砂浆界面发展较快,老砂浆与新砂浆结合较好;再生粗集料中天然粗集料老砂浆界面为混凝土浇筑前已存在的界面,并且存在着一定数量的微裂缝.再生粗集料混凝土3d抗压强度略高于普通混凝土,7,14,28d抗压强度则与普通混凝土基本相当.荷载作用下,再生粗集料混凝土内部裂纹主要分布在天然粗集料新砂浆界面以及天然粗集料老砂浆界面处. 相似文献
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井壁混凝土质量控制包括初步控制、生产控制和验收控制,为保证井壁混凝土质量达到设计性能指标,在施工全过程必须对其进行控制和管理。文中对各阶段控制内容和方法进行了阐述。 相似文献
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耿欧 《武汉理工大学学报(材料科学英文版)》2016,31(2):345-354
Based on the similarity theory, a new experimental method named Similar Experimental Method for Durability of Concrete (SEMDC) was established. The existing experimental methods for durability of concrete were summarized, and the merits and demerits of these experimental methods were analyzed. Major factors affecting the durability of concrete were found through literature review. These factors were analyzed and the similarity criteria were established according to the similarity theory, and then the SEMDC was established according to the rules of these criteria. The various influential factors of the experimental method were analyzed and the merits and demerits of this new experimental method were discussed. According to SEMDC, changing the geometry shrinkage ratio was the only way to accelerate the test in order to keep the experiment similar to the reality. There were few other parameters which need to be changed in SEMDC, making the test easy to be achieved. According to SEMDC, time shrinkage ratio was the square of geometric shrinkage ratio, so an appropriate increase of the geometric shrinkage ratio could accelerate the test. Finally, an example of experimental design for durability of concrete was devised theoretically base on SEMDC theory. 相似文献
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介绍了混凝土中钢筋腐蚀的电化学机理,总结了目前混凝土中钢筋腐蚀监测的研究成果及存在问题,提出了钢筋腐蚀监测今后发展的方向. 相似文献
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首先将由钢筋锈蚀导致的混凝土保护层胀裂的非均匀锈胀力模型简化为余弦函数锈胀力模型,然后应用弹性力学理论推导余弦函数锈胀力模型的计算公式,并探讨了影响钢筋锈胀力的各个因素,认为:钢筋混凝土间隙越大,混凝土开裂所需的临界锈蚀率越大,临界锈蚀率随着混凝土弹性模量的增加而增加,混凝土强度等级越高,临界锈蚀率越高,随着钢筋半径的增加混凝土起裂所需的锈蚀率减小,随着膨胀倍数的增加临界锈蚀率不断下降,膨胀倍数在2.5之前临界锈蚀率下降速度最快,膨胀倍数在2.5之后下降速度较为平缓。 相似文献
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在综合分析国内外再生骨料生产工艺的基础上,针对目前再生骨料生产方面存在的问题,提出了分类回收废弃混凝土,并针对不同类别废弃混凝土,制定各自生产工艺流程的分类专门化再生骨料生产模式与移动式再生骨料生产模式. 相似文献
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在相同人工气候条件下,研究再生集料混凝土(取代率为50%)与普通混凝土内部钢筋锈蚀速率的时变情况,得出再生混凝土钢筋锈蚀速率时变规律,分析其机理.并探讨了掺加粉煤灰对于再生混凝土和普通混凝土内钢筋锈蚀速率时变规律的影响. 相似文献