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Analysis of calcium leaching process and porosity change of mortar under environment of soft water


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Analysis of calcium leaching process and porosity change of mortar under environment of soft water
Yu JianZuo XiaobaoTang Yujuan
School of Science,Nanjing University of Science and Technology,Nanjing 210094,China
soft water environment cement mortar calcium leaching porosity Fick's law Gerard's solid-liquid equilibrium equation Ca(OH)2 weighing method
To get the effective experimental data of calcium leaching process for cement based material quickly,a model of calcium leaching of mortar in cylinder specimens under an environment of soft water is established using Fick's law and Gerard's solid-liquid equilibrium equation.Computing methods of porosity and Ca(OH)2 content for mortar in the leaching process are presented.Experiments on the accelerated leaching of the mortar specimens immersed into 6M NH4Cl solution with different water-cement ratio are carried out.A changing law of the porosity of these mortar specimens with leaching time is obtained by the weighing method.The porosities calculated by the model are compared with the experimental results to validate the model.The space-time changes of the porosity and Ca(OH)2 content of the mortar specimens are analyzed numerically.The results show that:the model is consistent with the experiments; in the scope of the leaching depth of the mortar specimens,the porosity increases with the leaching time,and the porosity of the surface for the mortar specimens increases rapidly in the initial stage of the leaching time; but the Ca(OH)2 content decreases with the increase of the leaching time,and decreases quickly at the beginning of leaching.


[1] 刘仍光,王强,阎培渝,等.不同水灰比水泥硬化浆体受软水溶蚀作用后的微结构变化差异[J].混凝土,2012(12):9-10,14.
Liu Rengguang,Wang Qiang,Yan Peiyu,et al.Difference between microstructure variation of hardened cement pastes with different water-to-cement ratios leached by soft water[J].Concrete,2012(12):9-10,14.
Jin Weiliang,Zhao Yuxi.State-of-the-art on durability of concrete structures[J].Journal of Zhejiang University(Engineering Science),2002,36(4):371-380,403.
[3]Sugiyama D,Fujita T.A thermodynamic model of dissolution and precipitation of calcium silicate hydrates[J].Cement and Concrete Research,2006,36(2):227-237.
[4]Haga K,Sutou S,Hironaga M,et al.Effects of porosity on leaching of Ca from hardened ordinary Portland cement paste[J].Cement and Concrete Research,2005,35(9):1764-1775.
[5]Jain J,Neithalath N.Analysis of calcium leaching behavior of plain and modified cement pastes in pure water[J].Cement and Concrete Composites,2009,31(3):176-185.
[6]Carde C,Francois R,Torrenti J M.Leaching of both calcium hydroxide and C-S-H from cement paste:Modeling the mechanical behavior[J].Cement and Concrete Research,1996,26(8):1257-1268.
Ruan Yan,Fang Kunhe,Zeng Li,et al.Experimental study on surface contact dissolution of hydraulic concrete[J].Journal of Building Materials,2007,10(5):528-533.
[8]Mainguy M,Tognazzi C,Torrenti J M,et al.Modeling of leaching in pure cement paste and mortar[J].Cement and Concrete Research,2000,30(1):83-90.
Liu Rengguang,Zhang Bo,Yan Peiyu.Microstructural variation of hardened cement-slag pastes leached by soft water[J].Journal of the Chinese Ceramic Society,2013,41(11):1487-1492.
[10]Rozière E,Loukili A,El Hachem R,et al.Durability of concrete exposed to leaching and external sulphate attacks[J].Cement and Concrete Research,2009,39(12):1188-1198.
[11]Alonso C,Castellote M,Llorente I,et al.Ground water leaching resistance of high and ultra high performance concretes in relation to the testing convection regime[J].Cement and Concrete Research,2006,36(9):1583-1594.
[12]Gerard B,Le Bellego C,Bernard O.Simplified modelling of calcium leaching of concrete in various environments[J].Materials and Structures,2002,35(254):632-640.
[13]Mindess S,Young J F,David D.Concrete[M].2nd ed.Beijing:Chemical Industry Press,2004:93.
[14]Nakarai K,Ishida T,Maekawa K.Modeling of calcium leaching from cement hydrates coupled with micro-pore formation[J].Journal of Advanced Concrete Technology,2006,4(3):395-407.
[15]Wan Keshu,Li Yan,Sun Wei.Experimental and modeling research of the accelerated calcium leaching of cement paste in ammonium nitrate solution[J].Construction and Building Materials,2013,40(92):832-846.


Last Update: 2016-06-30