裂缝对混凝土透水性的影响
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摘要
通过简单直观的试验方法验证裂缝增加了混凝土的透水性。试验采用的试件为U形梁,养护在室温(23℃)相对湿度为50%的环境中,通过加载使试件底部产生均匀裂缝,测量在不同的养护期,以试件质量的损失来评估裂缝对混凝土透水性的影响。试验数据结果表明:当试件的相对湿度大于周围环境相对湿度时,试件失水;差值越大,失水速度越快;当相对湿度减小到与周围环境相对湿度相等时,试件停止失水,失水率达到峰值。裂缝增加了这个过程的速度,加大了失水的速度,增加了混凝土的透水性。
Cracks increases concrete water permeability was proved by simple and visualized experimental method. U-shaped beam samples were used in the experiment. The specimens were cured at room temperature and50% relative humidity ambient environment. The specimens were produced cracks which are uniformly distributed in the bottom faces by bending on the both side of the U-shaped beams. The effect of concrete water permeability were analyzed due to cracking by measuring the water loss in real time. The data of the experiments shows that the water loss of specimens will happen when the relative humidity of specimens is larger than the ambient environment's. It will stop and the water loss percentage reaches plateau when the relative humidity of specimens equals to the ambient environments '. Cracks increase the speed of water loss and the evolution. It increases concrete water permeability.
Cracks increases concrete water permeability was proved by simple and visualized experimental method. U-shaped beam samples were used in the experiment. The specimens were cured at room temperature and50% relative humidity ambient environment. The specimens were produced cracks which are uniformly distributed in the bottom faces by bending on the both side of the U-shaped beams. The effect of concrete water permeability were analyzed due to cracking by measuring the water loss in real time. The data of the experiments shows that the water loss of specimens will happen when the relative humidity of specimens is larger than the ambient environment's. It will stop and the water loss percentage reaches plateau when the relative humidity of specimens equals to the ambient environments '. Cracks increase the speed of water loss and the evolution. It increases concrete water permeability.
引文
1 Wang K J,Jansen D C,Shah S P,et al.Permeability study of cracked concrete.Cement and Concrete Research,1997;27(3):381—393
2 Rapoport J,Aldea C M,Shah S P,et al.Permeability of cracked steel fiber-reinforced concrete.Journal of Materials in Civil Engineering,2002;14(4),355—358
3 Picandet V,Khelidj A,Bellegou H.Crack effects on gas and water permeability of concretes.Cement and Concrete Research,2009;39(6),537—547
4 Hutchinson T C,Soppe T E.Experimentally measured permeability of uncracked and cracked concrete components.Journal of Materials in Civil Engineering,2012;24(5):548—559
5 Yuan Y,Chi Y.Water permeability of concrete under uniaxial tension.Structural Concrete,2014;15(2):191—201
6 Rastiello G,Boulay C,Dal Pont S,et al.Real-time water permeability evolution of a localized crack in concrete under loading.Cement and Concrete Research,2014;56:20—28
7 Greenspan L.Humidity fixed-point of binary saturated aqueoussolutions.Journal of Research of the National Bureau of Standards Section A—Physics and Chemistry,1977;81(1):89—96
2 Rapoport J,Aldea C M,Shah S P,et al.Permeability of cracked steel fiber-reinforced concrete.Journal of Materials in Civil Engineering,2002;14(4),355—358
3 Picandet V,Khelidj A,Bellegou H.Crack effects on gas and water permeability of concretes.Cement and Concrete Research,2009;39(6),537—547
4 Hutchinson T C,Soppe T E.Experimentally measured permeability of uncracked and cracked concrete components.Journal of Materials in Civil Engineering,2012;24(5):548—559
5 Yuan Y,Chi Y.Water permeability of concrete under uniaxial tension.Structural Concrete,2014;15(2):191—201
6 Rastiello G,Boulay C,Dal Pont S,et al.Real-time water permeability evolution of a localized crack in concrete under loading.Cement and Concrete Research,2014;56:20—28
7 Greenspan L.Humidity fixed-point of binary saturated aqueoussolutions.Journal of Research of the National Bureau of Standards Section A—Physics and Chemistry,1977;81(1):89—96