西北地区干旱少雨,蒸发量大、昼夜温差大等恶劣的气候环境易导致混凝土开裂,合理的养护方式可提供混凝土硬化过程中必要的温湿度条件,提高混凝土抗裂性能。为研究干旱气候下养护方式对混凝土抗裂性能的影响,对混凝土裂缝宽度、开裂时间、裂缝长度和裂缝数目进行了统计和分析。结果表明:干旱地区恶劣气候条件易导致混凝土产生干缩裂缝,若不采取适宜的养护措施,在混凝土拆模后的一段时间内会造成混凝土开裂。试验发现:在恶劣气候条件下,塑料薄膜包裹养护、洒水养护等常规养护措施难以满足混凝土硬化时所需的温湿度条件,抗裂性能较差;蒸汽养护可有效防止混凝土早期开裂,亦可减少裂缝数目和抑制裂缝宽度的发展,提高混凝土抗裂性能。研究得出蒸汽养护方式可为特殊环境(干旱)下的混凝土预防开裂提供借鉴。
Abstract
Severe climate conditions in northwest China, such as drought, insufficient rain, large evaporation and large temperature difference between day and night are liable to lead to concrete cracking. Reasonable curing method provides necessary temperature and humidity conditions during concrete hardening and enhances the cracking resistance of concrete. In order to obtain the effect of curing method on the crack resistance of concrete in arid climate, we made a statistical analysis on the crack width, crack time, crack length and crack number of concretes. Results demonstrated that dry shrinkage cracks would occur after detaching the mold plates unless proper curing measures are taken. Under severe weather conditions, conventional curing measures such as plastic film wrapping and sprinkler curing could not meet the temperature and humidity conditions required for concrete hardening, resulting in poor crack resistance. Steam curing could effectively prevent early cracking of concrete, reduce the number of cracks and inhibit the development of crack width, and improve the crack resistance of concrete.
关键词
混凝土 /
抗裂性能 /
养护方式 /
干旱地区 /
干缩裂缝 /
蒸汽养护
Key words
concrete /
crack resistance /
curing method /
arid region /
desiccation crack /
steam curing
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参考文献
[1] 昆 建.现浇混凝土楼板裂缝控制工程实例钢筋混凝土裂缝控制指南.北京:化学工业出版社,2004.
[2] 王铁梦.钢筋混凝土结构的裂缝控制.安徽建筑,2001(1):1005-1013.
[3] 马丽媛,姚 燕,田 培,等. 国内外混凝土的收缩性能及抗裂性试验研究方法评述. 中国建材科技,2001(1):27-31.
[4] 蒋应军,陈忠达,彭 波,等. 密实骨架结构水泥稳定碎石路面配合比设计方法及抗裂性能. 长安大学学报(自然科学版),2002(4):9-12.
[5] 刘 竞,邓德华,刘赞群.养护措施和湿养时间对掺与未掺矿渣混凝土性能的影响.硅酸盐学报,2008,36(7):901-911.
[6] NAM H P,HOSODA A. Improvement of Crack Resistance of Slag Concrete by Utilizing High Alite Cement∥Proceedings of the Ninth International Conference on Creep, Shrinkage, and Durability Mechanics (CONCREEP-9). Cambridge, Massachusetts, United States: American Society of Civil Engineers, September 22-25, 2013, doi: 10.1061/9780784413111.042.
[7] BARR B, HOSEINIAN S B, BEYGI M A. Shrinkage of Concrete Stored in Natural Environments. Cement and Concrete Composites, 2003, 25(1): 19-29.
[8] 许彦辉. 风沙干燥地区无砟道床纤维混凝土抗裂性能研究. 科技创新导报,2016,13(19):42-43.
[9] 张戎令,王起才,刘树红,等. 极端大温差、干旱戈壁地区桥墩养护方法研究. 兰州交通大学学报,2014,33(4) :49-55.
[10] 赵文斌,刘建勋,张戎令,等.强风、干寒、大温差地区混凝土蒸汽养护与强度变化的规律.硅酸盐通报,2016,35(8):2358-2364.
[11] GB/T 50081—2002,普通混凝土力学性能试验方法标准.北京:中国建筑工业出版社,2003.
[12] JGJ 55—2000,普通混凝土配合比设计规程.北京:中国建筑工业出版社,2011.
[13] GB 50204—2015,混凝土结构工程质量验收规范.北京:中国建筑工业出版社,2014.
基金
长江学者和创新团队发展计划滚动支持项目(IRT_15R29);中国博士后科学基金资助项目(2016M602892);甘肃省高校协同创新科技团队支持计划项目(2017C-08);甘肃省交通运输厅科研项目( 201606)
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