不同水胶比高性能混凝土内部自干燥与干湿循环影响试验
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摘要
混凝土内部相对湿度是影响混凝土性能状态的重要因素。为研究不同水胶比、不同粉煤灰(FA)掺量对高性能混凝土自干燥效应的影响以及干湿循环过程中混凝土内部相对湿度(IRH)变化规律,首先对4种不同配合比的混凝土试件采用双层锡箔纸密封包裹处理,并对其自干燥现象持续70 d监测,然后对不掺粉煤灰0. 3水胶比的混凝土试件进行不同时段的浸水和自然干燥多次循环试验,模拟混凝土在干湿循环历程中其IRH变化规律。试验表明:在密封状态下,高性能混凝土内部相对湿度变化存在两个时期,即湿度饱和期(相对湿度100%)和湿度下降期;相同水胶比下,随着粉煤灰掺量的增加,混凝土的湿度饱和期增长,自干燥作用较缓慢,掺量35%FA的混凝土尤为明显; 0. 4水胶比掺35%FA的混凝土试件内部相对湿度基本无变化,几乎不存在自干燥现象。在干湿循环过程中,湿度上升(浸水)的速率明显大于湿度下降(干燥)的速率,随干燥时间增长,其内部相对湿度下降的速率逐渐变慢;随着干湿循环次数的增加,混凝土内部相对湿度变化速率逐渐减小。
The internal relative humidity of concrete plays an important role in the performance of concrete. Self-drying of high performance concrete is related to water-binder ratios and fly ash (FA)dosage. Whereas the change rule of internal related humidity (IRH) of concrete under wet-dry cycle is important. The self-drying of concrete specimens with four water-binder ratios,which were wrapped with tin foil,was monitored for 70 d. Then wet-dry cycle test of concrete specimen with the water-binder ratio of 0. 3 was conducted to investigate the change rule of IRH of concrete under soaking and naturally drying. The experiment results show that internal relative humidity of high-performance concrete in the sealed state has two periods,namely the humidity saturation period (relative humidity 100%) and the humidity drop period. With the same ratio of water to cement,the increase of fly ash content,the humidity saturation period of concrete increases,the self-drying effect slowly,and the concrete with 35% of concrete content is particularly noticeable. The concrete specimens which 0. 4 with water-binder ratio mixed with 35% fly ash is basically unchanged,there is almost no self-drying effect. Under dry-wet cycle environment,the rate of increase in humidity (water immersion) is significantly greater than the rate of decrease in humidity (dryness),as the drying time increases,the rate of decrease of its internal relative humidity gradually slows down. With the increase in the number of wet-dry cycles,the rate of change of the relative humidity inside the concrete gradually decreases.
The internal relative humidity of concrete plays an important role in the performance of concrete. Self-drying of high performance concrete is related to water-binder ratios and fly ash (FA)dosage. Whereas the change rule of internal related humidity (IRH) of concrete under wet-dry cycle is important. The self-drying of concrete specimens with four water-binder ratios,which were wrapped with tin foil,was monitored for 70 d. Then wet-dry cycle test of concrete specimen with the water-binder ratio of 0. 3 was conducted to investigate the change rule of IRH of concrete under soaking and naturally drying. The experiment results show that internal relative humidity of high-performance concrete in the sealed state has two periods,namely the humidity saturation period (relative humidity 100%) and the humidity drop period. With the same ratio of water to cement,the increase of fly ash content,the humidity saturation period of concrete increases,the self-drying effect slowly,and the concrete with 35% of concrete content is particularly noticeable. The concrete specimens which 0. 4 with water-binder ratio mixed with 35% fly ash is basically unchanged,there is almost no self-drying effect. Under dry-wet cycle environment,the rate of increase in humidity (water immersion) is significantly greater than the rate of decrease in humidity (dryness),as the drying time increases,the rate of decrease of its internal relative humidity gradually slows down. With the increase in the number of wet-dry cycles,the rate of change of the relative humidity inside the concrete gradually decreases.
引文
[1]蒋正武,孙振平,王培铭.水泥浆体中自身相对湿度变化与自收缩研究[J].建筑材料学报,2003,6(4):346-349.
[2]Pierre-Claude A,Neville A,Acker P.Intergraded view of shrinkage of defomation[J].Concret International,1997,19(9):1633-1638.
[3]蒋正武,孙振平,王新友,等.国外混凝土自收缩研究进展评述[J].混凝土,2001(4)30-33.
[4]Semion Z,Konstantin K.Influence of water to cement ratio on the efficiency of internal curing of high-performance concrete[J].Construction and Building Materials,2017,144:311-316.
[5]张君,韩宇栋,高原.混凝土自身与干燥收缩一体化模型及其在收缩应力计算中的应用[J].水利学报,2012(43):13-21.
[6]韩宇栋,张君,罗孙一鸣.水胶比和粗骨料体积分数对混凝土内部相对湿度及扩散系数的影响[J].建筑材料学报,2014,17(2):194-199.
[7]金祖权,赵铁军,王本臻,等.海洋环境下混凝土相对湿度响应[J].中南大学学报,2014,45(10):3608-3613.
[8]Shen D J,Wang T,Wang M G L,et al.Effect of internal curing with super absorbent polymers on the relative humidity of early-age concrete[J].Construction and Build Material,2015,99:246-253.
[9]Han Y D,Zhang J,Luo S Y,et al.Effect of internal curing on internal relative humidity and shrinkage of high concete slabs[J].Construction and Building Materials,2014,60(2):41-49.
[10]Li G T,Zhao X H.Properties of concrete incorporating fly ash and ground granulated blast fumace slag[J].Cement and Concrete Composites,2003,25(3):293-299.
[11]Shi H S,Xu B W,Zhou X H.Influence of mineral admixtures on compressive strength gas permeability and carbonation of high performance concrete[J].Construction and Building Materials,2009,23(5):1980-1985.
[12]谢友均,马昆林,刘宝举,等.复合超细粉煤灰混凝土的徐变性能[J].硅酸盐学报,2007,35(12):1637-1640.
[13]赵庆新,何小军,张津端.长期荷载作用对粉煤灰混凝土抗碳化性能的影响[J].硅酸盐学报,2017,45(2):255-259.
[14]Zuo J Q,Wu Y,Qin J J.Enhancing the thermoelectric properties in carbon fiber/cement composites by using steel slag[J].Key Engineering Materials,2013,539:103-107.
[15]蒋正武,孙振平,王培铭.矿物掺合料对混凝土内部相对湿度分布的影响[J].粉煤灰综合利用,2003(2):16-18.
[16]陈志亮.粉煤灰对混凝土内部相对湿度影响[J].粉煤灰综合利用,2013(5):32-33.
[17]高原,张君,孙伟.干湿循环下混凝土湿度与变形的测量[J].清华大学学报,2012,52(2):145-148.
[18]沈骏,袁梦,闫敏,等.海洋环境下干循环对结构混凝土性能影响研究现状、存在问题及其发展趋势[J].硅酸盐通报,2017,36(6):1930-1935.
[19]Li C Q,Li K F,Chen Z Y.Numerical analysis of moisture influential depth in concrete durability design[J].Tsinghua Science and Technology,2008,13(S1):7-12.
[20]Sobhan K,Gonzalez L,Reddy D V.Durability of a pavement foundation made form recycled aggregate concrete subjected to cyclic wet-dry exposure and fatigue loading[J].Materials and Structures,2015,8(27):1-14.
[21]黄瑜,祈錕,张君.早龄期混凝土内部湿度发展特征[J].清华大学学报(自然科学版)2007,47(3):310-312.
[22]Zhang J,Han Y D,Sun W.Experimental study on the relationship between shrinkage and interior humidity of concrete at early age[J].Magazine of Concrete Research,2010,62(3):191-199.
[23]Persson B.Moisture in concrete subjected to different kinds of curing[J].Materials and Structures,1997,30(9):533-544.
[24]王风平.掺合料对轻骨料混凝土内部相对湿度和干缩性能的影响[D].哈尔滨:哈尔滨工业大学,2008:20-30.
[25]覃维祖.粉煤灰在混凝土中应用技术[J].商品混凝土,2006,2:13-17.
[26]蒋正武,孙振平,王培铭.高性能混凝土自身相对湿度变化的研究[J].硅酸盐学报,2003,31(8):771-773.
[27]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,2013,16(3):376-380.
[2]Pierre-Claude A,Neville A,Acker P.Intergraded view of shrinkage of defomation[J].Concret International,1997,19(9):1633-1638.
[3]蒋正武,孙振平,王新友,等.国外混凝土自收缩研究进展评述[J].混凝土,2001(4)30-33.
[4]Semion Z,Konstantin K.Influence of water to cement ratio on the efficiency of internal curing of high-performance concrete[J].Construction and Building Materials,2017,144:311-316.
[5]张君,韩宇栋,高原.混凝土自身与干燥收缩一体化模型及其在收缩应力计算中的应用[J].水利学报,2012(43):13-21.
[6]韩宇栋,张君,罗孙一鸣.水胶比和粗骨料体积分数对混凝土内部相对湿度及扩散系数的影响[J].建筑材料学报,2014,17(2):194-199.
[7]金祖权,赵铁军,王本臻,等.海洋环境下混凝土相对湿度响应[J].中南大学学报,2014,45(10):3608-3613.
[8]Shen D J,Wang T,Wang M G L,et al.Effect of internal curing with super absorbent polymers on the relative humidity of early-age concrete[J].Construction and Build Material,2015,99:246-253.
[9]Han Y D,Zhang J,Luo S Y,et al.Effect of internal curing on internal relative humidity and shrinkage of high concete slabs[J].Construction and Building Materials,2014,60(2):41-49.
[10]Li G T,Zhao X H.Properties of concrete incorporating fly ash and ground granulated blast fumace slag[J].Cement and Concrete Composites,2003,25(3):293-299.
[11]Shi H S,Xu B W,Zhou X H.Influence of mineral admixtures on compressive strength gas permeability and carbonation of high performance concrete[J].Construction and Building Materials,2009,23(5):1980-1985.
[12]谢友均,马昆林,刘宝举,等.复合超细粉煤灰混凝土的徐变性能[J].硅酸盐学报,2007,35(12):1637-1640.
[13]赵庆新,何小军,张津端.长期荷载作用对粉煤灰混凝土抗碳化性能的影响[J].硅酸盐学报,2017,45(2):255-259.
[14]Zuo J Q,Wu Y,Qin J J.Enhancing the thermoelectric properties in carbon fiber/cement composites by using steel slag[J].Key Engineering Materials,2013,539:103-107.
[15]蒋正武,孙振平,王培铭.矿物掺合料对混凝土内部相对湿度分布的影响[J].粉煤灰综合利用,2003(2):16-18.
[16]陈志亮.粉煤灰对混凝土内部相对湿度影响[J].粉煤灰综合利用,2013(5):32-33.
[17]高原,张君,孙伟.干湿循环下混凝土湿度与变形的测量[J].清华大学学报,2012,52(2):145-148.
[18]沈骏,袁梦,闫敏,等.海洋环境下干循环对结构混凝土性能影响研究现状、存在问题及其发展趋势[J].硅酸盐通报,2017,36(6):1930-1935.
[19]Li C Q,Li K F,Chen Z Y.Numerical analysis of moisture influential depth in concrete durability design[J].Tsinghua Science and Technology,2008,13(S1):7-12.
[20]Sobhan K,Gonzalez L,Reddy D V.Durability of a pavement foundation made form recycled aggregate concrete subjected to cyclic wet-dry exposure and fatigue loading[J].Materials and Structures,2015,8(27):1-14.
[21]黄瑜,祈錕,张君.早龄期混凝土内部湿度发展特征[J].清华大学学报(自然科学版)2007,47(3):310-312.
[22]Zhang J,Han Y D,Sun W.Experimental study on the relationship between shrinkage and interior humidity of concrete at early age[J].Magazine of Concrete Research,2010,62(3):191-199.
[23]Persson B.Moisture in concrete subjected to different kinds of curing[J].Materials and Structures,1997,30(9):533-544.
[24]王风平.掺合料对轻骨料混凝土内部相对湿度和干缩性能的影响[D].哈尔滨:哈尔滨工业大学,2008:20-30.
[25]覃维祖.粉煤灰在混凝土中应用技术[J].商品混凝土,2006,2:13-17.
[26]蒋正武,孙振平,王培铭.高性能混凝土自身相对湿度变化的研究[J].硅酸盐学报,2003,31(8):771-773.
[27]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,2013,16(3):376-380.