孔隙率及含水率对混凝土气体渗透系数的影响
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摘要
采用圣保罗法(Cemburaeau法)研究了孔隙率及含水率与气体渗透系数之间的关系。结果表明,混凝土气体渗透性很大程度上取决于其含水率——含水率越大,混凝土的气体渗透性越差。绝干状态下混凝土的气体渗透系数与孔隙率间存在线性关系,而水平衡状态下两者间无明显相关性。VGM模型可有效拟合气体在混凝土中的渗透,简化了测试过程,且适用于各种不同配合比的混凝土。
Cembureau method is chosen to research the relationship of volumetric porosity,moisture content and concrete gas permeability coefficient.The results show concrete gas permeability coefficient depends on moisture content to a great extent--the bigger the moisture content,the worse the concrete gas permeability coefficient.The relationship of concrete gas permeability coefficient in absolutely dry condition and volumetric porosity is linearity,but they don′ t have apparent relationship in water balance state.The experimental results can be fitted by VGM model to describe the permeation of gas in concrete and can fit many kinds of concrete which have different mix proportion,which can simplify the process of testing.
Cembureau method is chosen to research the relationship of volumetric porosity,moisture content and concrete gas permeability coefficient.The results show concrete gas permeability coefficient depends on moisture content to a great extent--the bigger the moisture content,the worse the concrete gas permeability coefficient.The relationship of concrete gas permeability coefficient in absolutely dry condition and volumetric porosity is linearity,but they don′ t have apparent relationship in water balance state.The experimental results can be fitted by VGM model to describe the permeation of gas in concrete and can fit many kinds of concrete which have different mix proportion,which can simplify the process of testing.
引文
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[9]SANJUON M A,MUNOZ-MARTIALAY R.Oven-drying as a precon ditioning method for air permeability test on concrete[J].Materials Letters,1996,27(4):263-268.
[10]BASHEER L,BASHEER P A M,LONG A E.Influence of coarse aggregate on the permeation,durability and the microstructure characteristics of ordinary Portland cement concrete[J].Construction and Building Materials,2005,19(9):682-690.
[11]王中平,吴科如,张青云,等.混凝土气体渗透系数测试方法的研究[J].建筑材料学报,2001,4(4):317-321.
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[14]黄智德,彭志辉,彭家惠,等.NEL法测定海工混凝土氯离子扩散系数的应用研究[C]//全国混凝土耐久性学术交流会论文集.2008.
[15]HAMAMI A A,TURCRYY P,A魵T-MOKHTAR A.Influence of mix proportions on microstructure and gas permeability of cement pastes and mortars[J].Cement and Concrete Research,2012,42(2):490-498.
[16]LAFHAJ Z,GOUEYGOU M,DJERBI A,et al.Correlation between porosity,permeability and ultrasonic parameters of mortar with variable water/cement ratio and water content[J].Cement and Concrete Research,2006,36(4):625-633.
[17]HEEDE P V D,GRUYAERT E,BELIE N D.Transport properties of high-volume fly ash concrete:capillary water sorption,water sorption under vacuum and gas permeability[J].Cement and Concrete Composites,2010,32(10):749-756.
[18]杨通在,罗顺忠,许云书.氮吸附法表征多孔材料的孔结构[J].炭素,2006(1):17-22.
[19]SAVAGE B M,JANSSEN D J.Soil physics principles validated for use in predicting unsaturated moisture movement in portland cement concrete[J].Aci Materials Journal,1997,94(1):63-70.
[20]BAROGHEL-BOUNY V,MAINGUY M,LASSABATERE T,et al.Characte-rization and identification of equilibrium and transfer moisture properties for ordinary and high-performance cementitious materials[J].Cement and Concrete Research,1999,29(8):1225-1238.
[21]GENUCHTEN M T V.A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J].Soil Science Society of America Journal,1980,44(44):892-898.
[22]MUALEM Y.A new model for predicting the hydraulic conductivity of unsaturated porous media[J].Water Resources Research,1976,12(3):513-522.
[2]DHIR P K,HEWLETT F C,CHART Y N.Near surface characteristics of concrete:prediction of carbonation resistance[J].Magazine of Concrete Research,1989,41(148):122-128.
[3]LONG A E,BASHEER P A M,HENDERSON G,et a1.Concrete mix design methods[J].Thomas Telford,2009(21):220.
[4]SUGIYAMA T,BREMNER T W,TSUJI Y.Determination of chloride diffusion coefficient and gas permeability of concrete and their relationship[J].Cement and Concrete Research,1996,26(5):781-790.
[5]ABBAS A,CARCASSES M,OLLIVIER J P,et al.The importance of gas permeability in addition to the compressive strength of concrete[J].Magazine of Concrete Research,2000,52(1):1-6.
[6]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):l03-111.
[7]TSIVILIS S,CHANIOTAKIS E,BATIS G,et al.The effect of clinker and limestone quality on the gas permeability,water absorption and pore structure of limestone cement concrete[J].Cement and Concrete Composites,1999,21(2):139-146.
[8]MARTIN G R.A method for determining the relative permeability of concrete using gas[J].Magazine of Concrete Research,1986,38(135):90-94.
[9]SANJUON M A,MUNOZ-MARTIALAY R.Oven-drying as a precon ditioning method for air permeability test on concrete[J].Materials Letters,1996,27(4):263-268.
[10]BASHEER L,BASHEER P A M,LONG A E.Influence of coarse aggregate on the permeation,durability and the microstructure characteristics of ordinary Portland cement concrete[J].Construction and Building Materials,2005,19(9):682-690.
[11]王中平,吴科如,张青云,等.混凝土气体渗透系数测试方法的研究[J].建筑材料学报,2001,4(4):317-321.
[12]KAMECHE Z A,GHOMARI F,CHOINSKA M,et al.Assessment of liquid water and gas permeabilities of partially saturated ordinary concrete[J].Construction and Building Materials,2014,65(13):551-565.
[13]KLINKENBERG L J.The permeability of porous media to liquids and gases[J].Socar Proceedings,1941,2(2):200-213.
[14]黄智德,彭志辉,彭家惠,等.NEL法测定海工混凝土氯离子扩散系数的应用研究[C]//全国混凝土耐久性学术交流会论文集.2008.
[15]HAMAMI A A,TURCRYY P,A魵T-MOKHTAR A.Influence of mix proportions on microstructure and gas permeability of cement pastes and mortars[J].Cement and Concrete Research,2012,42(2):490-498.
[16]LAFHAJ Z,GOUEYGOU M,DJERBI A,et al.Correlation between porosity,permeability and ultrasonic parameters of mortar with variable water/cement ratio and water content[J].Cement and Concrete Research,2006,36(4):625-633.
[17]HEEDE P V D,GRUYAERT E,BELIE N D.Transport properties of high-volume fly ash concrete:capillary water sorption,water sorption under vacuum and gas permeability[J].Cement and Concrete Composites,2010,32(10):749-756.
[18]杨通在,罗顺忠,许云书.氮吸附法表征多孔材料的孔结构[J].炭素,2006(1):17-22.
[19]SAVAGE B M,JANSSEN D J.Soil physics principles validated for use in predicting unsaturated moisture movement in portland cement concrete[J].Aci Materials Journal,1997,94(1):63-70.
[20]BAROGHEL-BOUNY V,MAINGUY M,LASSABATERE T,et al.Characte-rization and identification of equilibrium and transfer moisture properties for ordinary and high-performance cementitious materials[J].Cement and Concrete Research,1999,29(8):1225-1238.
[21]GENUCHTEN M T V.A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J].Soil Science Society of America Journal,1980,44(44):892-898.
[22]MUALEM Y.A new model for predicting the hydraulic conductivity of unsaturated porous media[J].Water Resources Research,1976,12(3):513-522.