早龄期荷载与负温作用的井壁混凝土性能研究  

Research on the performance of shaft lining concrete under the effect of early-age load and negative temperature

作　　者：王祖琦[1] 刘娟红[1] 纪洪广[1] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083

出　　处：《混凝土》2015年第2期10-13,共4页Concrete

基　　金：国家自然科学基金资助项目(51174015)

摘　　要：对于冻结法施工的井壁混凝土,由于在早龄期受到了冻结土压力等荷载以及负温的作用,所引起的混凝土早期损伤会导致井壁混凝土耐久性下降。针对这些问题,研究了早龄期荷载和负温耦合作用对冻结竖井井壁C60混凝土抗压强度、氯离子扩散系数、声发射特征的影响。结果表明:在早龄期荷载和负温耦合作用下,随着早龄期荷载的增加,抗压强度明显下降,氯离子扩散系数有所提高,混凝土的渗透性由"中"变为"高",内部产生了更多的微裂缝,导致声发射"活跃阶段"提前出现;防冻剂的加入能提高在早龄期荷载和负温耦合作用下的混凝土抗压强度以及抗氯离子侵蚀性能;在混凝土中掺入仿钢纤维后可明显增加混凝土在早龄期荷载和负温耦合作用下的受荷载能力以及抗氯离子的渗透性能,对应的声发射信号相对稳定。For the shaft wall concrete under freezing construction, early -age frozen pressure load and negative temperature can cause early damage inside concrete and finally lead to the reduction of concrete durability. Aiming at these problems, it studied the coupling effect of early - age load and negative temperature on the strength, chloride diffusion and acoustic emission characteristic of freezing shaft wall C60 concrete.The results show that under the coupling effect of early -age load and negative temperature, with the increase of early - age load, compression strength descends obviously and chloride diffusion coefficient increases apparently, concrete permeabili- ty changes from＂ middle＂ to＂ high＂, the internal micro cracks and deficiency leads to advancing the active phase of acoustic emission; Antifreeze can improve compression strength and the resistance to chloride ion under the coupling effect of early - age load and negative temperature ;adding imitation of steel fibers in concrete can improve the load -beating capacity and anti -chloride ion permeability of the concrete under the coupling effect of early - age load and negative temperature and the corresponding acoustic emission signal is rel- atively stable.

关 键 词：早龄期荷载 负温 井壁混凝土 氯离子扩散性 声发射特征 

分 类 号：TU528.01[建筑科学—建筑技术科学]