核电站安全壳混凝土气体密封性研究
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摘要
以核电站安全壳同配比混凝土为研究对象,首先研究了混凝土氮气和水汽的等温吸附曲线,然后采用喷淋水的方式由表及里地润湿混凝土,测试混凝土的饱和度和气体渗透率的变化规律,最终分析了提高混凝土安全壳密封性的有效措施。研究结果表明:随着相对湿度的增加,混凝土的饱和度逐渐增大,气体渗透率逐渐降低;喷淋水的方法可以在135 d使安全壳混凝土的润湿厚度达到120～150 mm,饱和度达到0. 7～0. 9,渗透率由10~(-16)～10~(-17)m~2降低至10~(-18)～10~(-19)m~2,混凝土安全壳的密封性能大幅提升;氮气吸附和水汽吸附结果均表明孔径体积在10～100 nm有较大增加,故采取措施封堵混凝土10～100 nm的孔隙结构是有效阻止混凝土气体渗透的有效途径。
The adsorption isotherm curves of nitrogen and water vapor in the concrete of nuclear power plant containment were studied. Then concrete samples were wetted by spraying water to the cross section and variation of concrete saturation and gas permeability along the sample length were tested. Finally,effective measures to enhance the sealing performance of the concrete containment are analysed and discussed. Results show that the concrete saturation increases and the gas permeability decreases gradually with the increas of relative humidity. By 135 d water spraying,the wetting thickness of containment concrete reaches 120-150 mm, the saturation reaches 0. 7-0. 9 and the permeability decreases from 10~(-16)-10~(-17) m~2 to 10~(-18)-10~(-19) m~2. This effectively improves the sealing performance of concrete. Nitrogen and water vapor adsorption show that the pore volume is mainly located in the range of 10-100 nm and thus plugging the pore structure of 10-100 nm is an effective way to effectively prevent gas permeation of concrete.
The adsorption isotherm curves of nitrogen and water vapor in the concrete of nuclear power plant containment were studied. Then concrete samples were wetted by spraying water to the cross section and variation of concrete saturation and gas permeability along the sample length were tested. Finally,effective measures to enhance the sealing performance of the concrete containment are analysed and discussed. Results show that the concrete saturation increases and the gas permeability decreases gradually with the increas of relative humidity. By 135 d water spraying,the wetting thickness of containment concrete reaches 120-150 mm, the saturation reaches 0. 7-0. 9 and the permeability decreases from 10~(-16)-10~(-17) m~2 to 10~(-18)-10~(-19) m~2. This effectively improves the sealing performance of concrete. Nitrogen and water vapor adsorption show that the pore volume is mainly located in the range of 10-100 nm and thus plugging the pore structure of 10-100 nm is an effective way to effectively prevent gas permeation of concrete.
引文
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[2]Chen X T,Davy C A,Shao J F,et al.Experimental and micro-mechanical analysis of the mechanical and transport properties of mortar containing heat-induced micro-cracks[J].Cement&Concrete Composites,2010,32(9):678-685.
[3]桂强,秦敏峰,李克非.水泥基材料气体渗透性研究进展[J].硅酸盐学报,2015,43(10):1500-1510.
[4]Chen W,Liu J,Brue F,et al.Water retention and gas relative permeability of two industrial concretes[J].Cement and Concrete Research,2012,42(7):1001-1013.
[5]Liu J,Agostini F,Skoczylas F.From relative gas permeability to in situ saturation measurements[J].Construction and Building Materials,2013,40:882-890.
[6]罗明勇.大掺量矿渣水泥基材料孔隙结构与透气性研究[D].北京:清华大学,2013.
[7]罗明勇,桂强,李克非.孔隙结构及饱水度对水泥基材料透气性的影响[J].硅酸盐学报,2014,42(8):974-980.
[8]宋杨,金文娟.高温后混凝土气体渗透性及力学性能研究[J].硅酸盐通报,2018,37(1):290-296.
[9]Burlion N,Gong F C,Carlier J P.Evaluation expérimentale des propriétés hydrodynamiques des matériaux cimentaires[C].Congres Fransais De Me'canique.AFM,Masion De La Me'canique,Courbevoie,2007.
[10]王中平,黄晨明,王弢.核磁共振冷冻测孔法测量水泥基材料孔径分布研究[J].建筑材料学报,2012,15(1):6-10.