自密实混凝土高温爆裂性能影响因素的试验研究  

Experimental study of factors affecting the spalling of self-compacting concrete under high temperatures

作　　者：陶津[1] 柳献[2] 袁勇[2] Luc Taerwe 

机构地区：[1]东南大学,江苏南京210096 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]比利时根特大学Magnel混凝土实验室

出　　处：《土木工程学报》2009年第10期22-26,共5页China Civil Engineering Journal

基　　金：国家科技支撑计划(2006BAJ27B02-02);上海市科委(08210705700)

摘　　要：对自密实混凝土、掺加聚丙烯纤维的自密实混凝土与高强混凝土进行高温爆裂试验,对不同升温速率、不同聚丙烯纤维掺量、不同应力水平进行综合研究。为了清楚地了解自密实混凝土在高温下爆裂的本质特征,通过环境扫描电镜和汞压力测孔法对混凝土高温下微观性能进行研究,还进行高温后材料的气渗性能测试。分析初始应力、纤维掺量、不同升温机制等对混凝土爆裂性能的影响,建立自密实混凝土高温爆裂性能与微观组成结构之间的联系,揭示不同影响因素对自密实混凝土高温爆裂性能产生影响的本质原因。试验结果表明初始应力是影响自密实混凝土爆裂的重要因素,且一定掺量的聚丙烯纤维对抑制自密实混凝土高温爆裂具有显著的作用,最后探讨聚丙烯纤维作用机理,提出自密实混凝土高温爆裂抑制措施,对于自密实混凝土的大规模推广和应用具有重要实际意义。Experiments were performed for several types of high performance concrete, including high strength concrete and self compacting concrete （SCC） with different polypropylene fibers dosages. The effects of different heating rates, stress levels and polypropylene fiber contents on the spalling of concrete were studied. After a special heating process, scanning electron microscopy （SEM） and mercury instruction porosimetry （MIP） were employed to investigate the microstructure of concrete exposed to high temperature. Gas permeability test was carried out in order to determine the effect of microstructural changes on permeability. Based on the results, the relationship between spalling and mierostructure of concrete was studied, and the mechanisms of factors that influence spalling were analyzed. The results of test showed that a certainamount of polypropylene fiber could minimize the risk of spalling for self-compacting concrete at high temperatures. The effect of stress level on spalling was significant. The probability of spalling was higher for specimens in compression than for unloaded specimens. Some measures were proposed to minimize the risk of spalling of self-compacting concrete.

关 键 词：自密实混凝土 高温 爆裂 聚丙烯纤维 

分 类 号：TU37[建筑科学—结构工程]