EXPERIMENTAL INVESTIGATION ON CONCRETE PERFORATED BRICK WALL SHINKAGE AT DIFFERENT AGES
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摘要: 由于收缩大、含水率高,施工规范不允许使用未达到龄期的混凝土砖,然而由于种种原因,工程中尚有未达到标准龄期的混凝土砖大量使用的现实情况,需要工程技术人员认识这种材料的特性,并对已经上墙的材料提出修复措施。对不同龄期混凝土砖墙体的收缩变形规律进行试验研究。首先对单块砖进行了含水率、抗压强度等指标的测定;然后对不同龄期砌筑的墙体进行了持续测试,包括墙体端部位移和即时应变;最后进行分析和估算,并提出工程限制措施建议。试验表明:部分未达到标准龄期混凝土砖块体在不同湿度环境下表现出初期湿胀的特点;墙体收缩表现出现干缩和湿胀循环,墙体的初期收缩率在1.610-4~2.010-4;测试得到的墙体即时应变初期表现为受压状态,随后转为受拉状态并趋于稳定;不同龄期混凝土砖墙体的初期即时应变与时间的关系近似服从指数下降规律。得出的结论为控制干缩裂缝和未到龄期混凝土砖上墙后的修复提供依据,对于正确认识不同龄期混凝土砖墙体的特性、指导工程实践具有现实意义。Abstract: It is forbidden to use concrete perforated brick(CPB)wall at early ages for its big shringkage and high water content, Nevertheless, there are still many applications in engineering practice due to various reasons.Engineers should recognize their characteristics, then decide how to repair the walls.Experimental investigation is carried out in this study including bricks and walls.Firstly bricks are tested with water content, compressive strength, and etc;then whole walls at diffirent ages are tested with walls' end deformations and instantaneous strains;at last analysis and estimations are done and engineering restrictions are proposed.It is concluded that some early-age CPB bricks have wet inflations, whereas CPB walls have wet inflation and dry shrinkage circulations.Its shinkage rate is about 1.6~2.010-4.Walls' instantaneous strains show a pressure characreristic at beginning and then to tensile, and tend to be stable at last.Relationship between instantaneous strain and time(age)has an exponential decay trend.Results obtained in this study help engineers to control cracks and repair walls, It reflects the basic characteristics of walls at different ages, and thus has relevant engineering significance.
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Key words:
- shinkage /
- age /
- concrete perforated brick( CPB) /
- experimental investigation
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[2] 黄丽华,赵成文,高连玉,等.混凝土小型砌块墙体的干缩变形研究[J].建筑砌块与砌块建筑,2006(6):10-12. 黄世雄.石渣粉混凝土空心砌块墙体裂缝调查与对策分析[J].福建建筑,2003(130):45-47. [3] 刘立新,田高燕,赵文兰,等.混凝土多孔砖收缩性能研究[J].郑州大学学报:工学版,2008,29(4):77-80. [4] 梁建国,程少辉.混凝土砖收缩特性试验研究[J].湖南大学学报:自然科学版,2008,35(11):17-20. [5] 汪博,赵成文.工业废渣混凝土多孔砖墙体干缩性能实验研究[J].山西建筑,2009,35(4):12-14. [6] 金伟良,岳增国.框架砌体填充墙收缩裂缝成因与控制研究[R].杭州:浙江大学研究报告,2009. [7] 杨芳.砂加气混凝土干燥收缩性能的试验研究[J].新型建筑材料,2006(5):49-51. [8] 牛季收.对加气混凝土砌块墙体收缩裂缝的研究[J].混凝土,2007(3):92-94. [9] 唐明,姜丽波.新型块体墙材单体干燥收缩特征试验[J].沈阳建筑大学学报,2009,25(5):942-947. [10] 张玉红,唐岱新,李作为,等.砌块墙体二次干缩的试验研究[J].哈尔滨建筑大学学报,2002(2):34-37. [11] 李作为,李惠,唐岱新.收缩应力下砌块墙体裂缝防治技术实验研究及理论分析[J].混凝土,2004,171(1):52-53. [12] 周瑾,陈鸣,金伟良,等.混凝土小型空心砌块墙体干缩性能的试验研究[J].工业建筑,2004,34(8):41-44. [13] 孙林柱,金国平.加气混凝土砌块和砂浆组合模型收缩的研究[J].武汉理工大学学报,2006,28(12):89-92. [14] 赵文兰,刘立新,蔡秀兰,等.蒸压粉煤灰砖前提收缩变形性能试验研究[J].建筑科学,2009,25(11):59-62. [15] Van Zijl G P A G, Vries P A, Vermeltfoort A T. Masonry Wall?Damage by Restraint to Shinkage [J]. Journal of Structural?Engineering,2004(6):1075-1086. [16] GB/T 41111997混凝土小型空心砌块试验方法[S]. [17] 李庆繁.混凝土墙材制品干燥收缩性能及有关问题的探讨[J].墙材革新与建筑节能,2006(3):21-24. [18] 浙江省建筑设计研究院.混凝土多孔砖建筑技术规程[M].杭州:浙江大学出版社,2003. [19] 王铁梦.工程结构裂缝控制[M].北京:中国建筑工业出版社,2005. [20] C de Sa, Benboudjema F, Thiery M, et al. Analysis of?Microcracking Induced by Defferential Drying Shrinkage [J]. Cement and Concrete Composites,2008(30):947-956. [21] GB 500032001.砌体结构设计规范[S]. [22] 刘立新,谢丽丽,巩耀娜.混凝土多孔砖和普通砖砌体的受力性能及工程应用研究[C]//砌体结构理论与新型墙材应用.北京:中国城市出版社,2007.
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