干湿交替下混凝土内部相对湿度变化规律
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国家自然科学基金资助项目(51178248);国家重点基础研究发展计划(973计划)项目(2009CB623200)


Experimental Study on the Internal Relative Humidity inConcrete under Dry Wet Cycles
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    摘要:

    分别采用清水和硫酸盐溶液作为湿润溶液,对C30和C80这2个强度等级混凝土进行了干湿交替试验,测量了干湿交替下混凝土不同深度处的相对湿度随时间的发展规律.结果表明:在覆膜养护阶段,混凝土内部相对湿度的发展遵循两阶段发展模式,即首先经历一段湿度饱和期(湿度为100%),然后进入湿度下降期;混凝土内部相对湿度沿高度呈现明显的梯度;当混凝土进入干湿交替过程后,只有距混凝土表层一定深度范围内的相对湿度发生变化,大于此深度处的混凝土相对湿度基本保持不变,此深度即为干湿交替影响深度;不同强度等级混凝土在相同干湿交替条件下影响深度不同,混凝土水灰比越小,强度等级越高,影响深度越小;湿润过程采用硫酸盐溶液时,混凝土的干湿交替影响深度要比采用清水时大.

    Abstract:

    Using clean water and sulfate solution as the wetting medium,the internal relative humidity in concrete under dry wet cycles was measured. The test results show that at the beginning of concrete placement, the variation law of the internal relative humidity in concrete with age can be described by a water vapor saturated stage with 100% relative humidity followed by a stage that relative humidity gradually decreases and significant humidity gradient along the height can be found. Under dry wet cycles, the changes of the relative humidity occur just within a certain depth from the concrete surface. This depth is commonly known as the influencing depth. Under the same dry wet cycles, different influencing depths were observed for concretes with different strength. The lower the water to cement ratio and/or the higher the concrete strength, the shorter the influencing depth. The influencing depth is larger when sulfate solution is used as the wetting medium than that when the clean water is used.

    参考文献
    [1]HOBBS D W,MATTHEWS J D,MARSH B K. Minimum requirements of durable concrete:Carbonation and chloride induced corrosion,freeze thaw attack and chemical attack[M].Crowthorne:British Cement Association,1998:1 3.
    [2]MCCARTER W J,WATSON D W,CHRISP T M.Surface zone concrete:Drying,absorption,and moisture distribution[J].ASCE Journal of Materials in Civil Engineering,2001,13(1):49 57.
    [3]ANDRADE C,SARRIA J,ALONSO C.Relative humidity in the interior of concrete exposed to natural and artificial weathering[J].Cement and Concrete Research,1999,29(8):1249 1259.
    [4]PARROTT L J.Influence of cement type and curing on the drying and air permeability of cover concrete[J].Magazine of Concrete Research,1995,47(171):103 111.
    [5]NILSSON L O.Long term moisture transport in high performance concrete[J].Materials and Structures,2002,35(10):641 649.
    [6]ZHANG J,HUANG Y,QI K.The interior relative humidity of normal and high strength concrete at early age[J].ASCE Journal of Materials in Civil Engineering,2012,24(6):615 622.
    [7]ZHANG Jun,HOU Dong wei,HAN Yu dong.Micromechanical modeling on autogenous and drying shrinkages of concrete[J].Construction and Building Materials,2012,29(3):230 240.
    [8]张君,侯东伟,高原.混凝土自收缩与干燥收缩的统一内因[J].清华大学学报:自然科学版,2010,50(9):1321 1324.
    ZHANG Jun,HOU Dong wei,GAO Yuan.Investigation on the uniform driving force of autogenous and drying shrinkage of concrete[J].Journal of Tsinghua University:Sci and Tech,2010,50(9):1321 1324.(in Chinese)
    [9]ZHANG J,QI K,HUANG Y.Calculation of moisture distribution in early age concrete[J].ASCE Journal of Engineering Mechanics,2009,135(8):871 880.
    [10]李春秋.干湿交替下表层混凝土中水分与离子传输过程研究[D].北京:清华大学,2009.
    LI Chun qiu.Study on water and lonic transport processes in cover concrete under drying wetting cycles[D].Beijing:Tsinghua University,2009.(in Chinese)
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高原,张君,韩宇栋.干湿交替下混凝土内部相对湿度变化规律[J].建筑材料学报,2013,(3):375-381

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  • 收稿日期:2011-11-29
  • 最后修改日期:2012-02-10
  • 在线发布日期: 2013-07-15
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