不同强度等级混凝土等温干燥脱水规律
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摘要
通过电热恒温鼓风干燥箱在60,80,105,120,150℃下分别对C20,C30,C40,C50这4个强度等级的混凝土进行干燥,分析其干燥速率、完全干燥所需时间和失水量等的变化规律.结果表明:在相同干燥温度下,混凝土强度等级越高,干燥速率越小,完全干燥所需时间越长,总失水量越少;相同强度等级混凝土在干燥时,干燥温度越高,干燥速率越大,完全干燥所需时间越短,总失水量越多;当干燥温度高于80℃时,混凝土中的结晶水开始失去,且干燥温度越高,结晶水失去越多;基于修正Page模型Ⅱ,考虑干燥温度和混凝土强度等级的影响,得到了适用于C20～C50混凝土在60～150℃下的干燥模型.
Concretes with different strength grades were dried in a thermostatic electric drier with forced convection at 60,80,105,120,150℃.The change of drying rate,completely drying time and amount of water loss were analyzed.The results show that under the same temperature,with the increase of concrete strength grade,the drying rate becomes smaller,the completely drying time becomes longer,and the total amount of water loss becomes less.With the same strength grade of concrete,the drying rate is higher,the completely drying time is less,and the total amount of water loss is more under higher drying temperature.When drying temperature is higher than 80℃,the crystal water begins to loss,and the higher drying temperature,the more crystal water loss.According to the modified Page modelⅡ,a model of drying for C20-C50 concrete at 60-150℃is established considering the effects of drying temperature and strength grade.
Concretes with different strength grades were dried in a thermostatic electric drier with forced convection at 60,80,105,120,150℃.The change of drying rate,completely drying time and amount of water loss were analyzed.The results show that under the same temperature,with the increase of concrete strength grade,the drying rate becomes smaller,the completely drying time becomes longer,and the total amount of water loss becomes less.With the same strength grade of concrete,the drying rate is higher,the completely drying time is less,and the total amount of water loss is more under higher drying temperature.When drying temperature is higher than 80℃,the crystal water begins to loss,and the higher drying temperature,the more crystal water loss.According to the modified Page modelⅡ,a model of drying for C20-C50 concrete at 60-150℃is established considering the effects of drying temperature and strength grade.
引文
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[15]冯竟竟.水泥基材料高温微细观劣化与损伤过程的试验研究[D].北京:中国矿业大学(北京),2009.FENG Jingjing.Experimental study on the microstructure deterioration and damage process of cement-based materials exposed to high temperatures[D].Beijing:China University of Mining and Technology(Beijing),2009.(in Chinese)
[16]阎继红.高温作用下混凝土材料性能试验研究及框架结构性能分析[D].天津:天津大学,2000.YAN Jihong.Experimental study of concrete behaviour analysis of reinforced concrete frame under high temperature[D].Tianjin:Tianjin University,2000.(in Chinese)
[17] ZHANG Guohui,LI Zongli,ZHANG Linfei,et al.Experimental research on drying control condition with minimal effect on concrete strength[J].Construction and Building Materials,2017,135:194-202.
[18] BABALIS S J,PAPANICOLAOU E,KYRIAKIS N,et al.Evaluation of thin-layer drying models for describing drying kinetics of figs(Ficus carica)[J].Journal of Food Engineering,2006,75(2):205-214.
1)文中涉及的用水量、含泥量等均为质量分数.
[2]张永亮.干燥和饱和混凝土动静态力学特性试验及理论研究[D].合肥:合肥工业大学,2015.ZHANG Yongliang.Experimental and theoretical study on the static and dynamic mechanical properties of dry and saturated concrete[D].Hefei:Hefei University of Technology,2015.(in Chinese)
[3]宋来忠,张伟朋,周斌,等.混凝土动态劈拉特性及损伤机理研究[J].三峡大学学报(自然科学版),2015,37(6):10-14.SONG Laizhong,ZHANG Weipeng,ZHOU Bin,et al.Dynamic splitting tensile behavior and damage mechanism of concrete[J].Journal of China Three Gorges University(Natural Sciences),2015,37(6):10-14.(in Chinese)
[4]王海龙,李庆斌.不同加载速率下干燥与饱和混凝土抗压性能试验研究分析[J].水力发电学报,2007(1):84-89.WANG Hailong,LI Qingbin.Experiments of the compressive properties of dry and saturated concrete under different loading rates[J].Journal of Hydroelectric Engineering,2007(1):84-89.(in Chinese)
[5]刘保东,李鹏飞,李林,等.混凝土含水率对强度影响的试验[J].北京交通大学学报,2011,35(1):9-12.LIU Baodong,LI Pengfei,LI Lin,et al.Experimental study on influence of water content on concrete strength[J].Journal of Beijing Jiaotong University,2011,35(1):9-12.(in Chinese)
[6]李鑫鑫.孔隙水对混凝土静力特性的影响研究[D].重庆:重庆交通大学,2011.LI Xinxin.Pore water influence to static mechanical properties of concrete[D].Chongqing:Chongqing Jiaotong University,2011.(in Chinese)
[7]冯驰,吴晨晨,冯雅,等.干燥方法和试件尺寸对加气混凝土等温吸湿曲线的影响[J].建筑材料学报,2014,17(1):132-137,142.FENG Chi,WU Chenchen,FENG Ya,et al.Effect of drying methods and sample sizes on moisture absorption isotherms of aerated concrete[J].Journal of Building Materials,2014,17(1):132-137,142.(in Chinese)
[8] YURTDAS I,BURLION N,SHAOE J F,et al.Evolution of the mechanical behaviour of a high performance self-compacting concrete under drying[J].Cement and Concrete Composites,2010,33(3):380-388.
[9] CADONI E,LABIBES K,ALBERTINI C,et al.Strain-rate effect on the tensile behaviour of concrete at different relative humidity levels[J].Materials and Structures,2001,34(1):21-26.
[10]张国辉,李宗利,张林飞,等.干燥条件对混凝土强度影响试验研究[J].建筑材料学报,2015,18(5):840-846.ZHANG Guohui,LI Zongli,ZHANG Linfei,et al.Experimental study on concrete strength for different drying conditions[J].Journal of Building Materials,2015,18(5):840-846.(in Chinese)
[11]孙金阳.混凝土湿润与干燥过程中水分传输规律研究[D].杭州:浙江大学,2012.SUN Jinyang.Research on moisture transport under wetting and drying conditions[D].Hangzhou:Zhejiang University,2012.(in Chinese)
[12]韩涛,靳秀芝,王慧奇,等.高温对水泥石结构和性能的影响及机理分析[J].中北大学学报(自然科学版),2015,36(3):378-383.HAN Tao,JIN Xiuzhi,WANG Huiqi,et al.Influence and mechanism analysis of high temperature on the structure and properties of hydrated cement pastes[J].Journal of North University of China(Natural Science),2015,36(3):378-383.(in Chinese)
[13]林宗寿.胶凝材料学[M].武汉:武汉理工大学出版社,2014:72.LIN Zongshou.Cementitious material science[M].Wuhan:Wuhan University of Technology Press,2014:72.(in Chinese)
[14]柳献,袁勇,叶光,等.高性能混凝土高温微观结构演化研究[J].同济大学学报(自然科学版),2008,36(11):1473-1478.LIU Xian,YUAN Yong,YE Guang,et al.Study on pore structure evolution of high performance concrete with elevated temperatures[J].Journal of Tongji University(Natural Science),2008,36(11):1473-1478.(in Chinese)
[15]冯竟竟.水泥基材料高温微细观劣化与损伤过程的试验研究[D].北京:中国矿业大学(北京),2009.FENG Jingjing.Experimental study on the microstructure deterioration and damage process of cement-based materials exposed to high temperatures[D].Beijing:China University of Mining and Technology(Beijing),2009.(in Chinese)
[16]阎继红.高温作用下混凝土材料性能试验研究及框架结构性能分析[D].天津:天津大学,2000.YAN Jihong.Experimental study of concrete behaviour analysis of reinforced concrete frame under high temperature[D].Tianjin:Tianjin University,2000.(in Chinese)
[17] ZHANG Guohui,LI Zongli,ZHANG Linfei,et al.Experimental research on drying control condition with minimal effect on concrete strength[J].Construction and Building Materials,2017,135:194-202.
[18] BABALIS S J,PAPANICOLAOU E,KYRIAKIS N,et al.Evaluation of thin-layer drying models for describing drying kinetics of figs(Ficus carica)[J].Journal of Food Engineering,2006,75(2):205-214.
1)文中涉及的用水量、含泥量等均为质量分数.