C_4A_3$-CaSO_4-CaO体系在硅酸盐水泥浆体中的膨胀机理
|
摘要
对C_4A_3$-CaSO_4-CaO体系(CCC体系,C_4A_3$为4CaO·3Al_2O_3·SO_3)的膨胀机理进行探讨。X射线衍射谱、水化放热历程和封闭环境下的体积变化测试结果表明:CCC体系中CaO的水化活性显著大于其它两者,CaO在水化早期表现出剧烈的水化放热行为,并产生剧烈而短暂的膨胀;CCC体系水化的目标产物是氢氧化钙和钙矾石,但生成钙矾石不是产生宏观膨胀的充要条件,适宜的钙矾石生成位置可以使其在C4A3$颗粒表面,通过钙矾石生长过程中产生的颗粒互斥效应产生膨胀;钙矾石生成过程的膨胀机理,除了吸水肿胀和结晶生长外,还有孔隙形成机理。CCC体系中CaO和CaSO_4的存在有利于保障钙矾石的生成位置。使用CaO-SO_3~-Al_2O_3三元相图表征了CCC体系的组成与水化产物之间的关系,并给出了适宜组成的CCC体系在三元相图中的存在区域。
The expansion mechanism of C_4A_3$-CaSO_4-CaO(CCC system, C4A3$ is 4CaO·3Al2O3·SO3) was discussed. Based on the results obtained by X-ray diffraction, hydration heat releasing process and volume change during hydration, it is manifested that the reactivity of CaO overwhelms that of C4A3$ and Ca SO4, and introducing CaO to cement paste results in an intensive hydration heat releasing behavior and an expansion in early hydration period. Producing ettringite cannot guarantee the expansion of cement paste because ettringite forming location is also a decisive factor. The suitable forming location of ettringite should be on the surface of C4A3$ particle, and the growth of ettringite results in expansion. The expansion mechanism of CCC system could be due to the porosity enhancing other than the swelling and the crystal growth. From the thermodynamic and kinetic point of view, it is manifested that the existence of CaO and Ca SO4 in CCC system promotes the forming tendency of ettringite on the surface of C4A3$ particle. CaO-SO_3-Al_2O_3 three phases diagram was used to character the relationship between the composition of CCC system and its hydration products. The suitable region of CCC system in the three phases diagram was recommended.
The expansion mechanism of C_4A_3$-CaSO_4-CaO(CCC system, C4A3$ is 4CaO·3Al2O3·SO3) was discussed. Based on the results obtained by X-ray diffraction, hydration heat releasing process and volume change during hydration, it is manifested that the reactivity of CaO overwhelms that of C4A3$ and Ca SO4, and introducing CaO to cement paste results in an intensive hydration heat releasing behavior and an expansion in early hydration period. Producing ettringite cannot guarantee the expansion of cement paste because ettringite forming location is also a decisive factor. The suitable forming location of ettringite should be on the surface of C4A3$ particle, and the growth of ettringite results in expansion. The expansion mechanism of CCC system could be due to the porosity enhancing other than the swelling and the crystal growth. From the thermodynamic and kinetic point of view, it is manifested that the existence of CaO and Ca SO4 in CCC system promotes the forming tendency of ettringite on the surface of C4A3$ particle. CaO-SO_3-Al_2O_3 three phases diagram was used to character the relationship between the composition of CCC system and its hydration products. The suitable region of CCC system in the three phases diagram was recommended.
引文
[1]韩建国,阎培渝.C4A3$-Ca SO4-Ca O体系在硅酸盐水泥浆体中的膨胀能力[J].硅酸盐学报,2016,44(8):1120–1125.HAN Jianguo,YAN Peiyu.J Chin Ceramic Soc,2016,44(8):1120–1125.
[2]KLEIN A,TROXELL G E.Studies of calcium sulfoaluminate admixtures for expansive cements[C].ASTM Proceedings,1958,58:968–1008.
[3]KLEIN A,KARBY T,POLIVKA M.Properties of an expansive cement for chemical prestressing[C].ACI J Proceedings ACI,1961,58(7):59–82.
[4]MEHTA P K.Expansion characteristics of calcium sulfoaluminate hydrates[J].J Am Ceram Soc,1967,50(4):204–208.
[5]MEHTA P K.Mechanism of expansion associated with ettringite formation[J].Cem Concr Res,1973,3(1):1–6.
[6]OGAWA K,ROY D M.C4A3$hydration ettringite formation,and itsexpansion mechanism:I.expansion;Ettringite stability[J].Cem Concr Res,1981,11(5/6):741–750.
[7]OGAWA K,ROY D M.C4A3$hydration,ettringite formation,and its expansion mechanism:II.Microstructural observation of expansion[J].Cem Concr Res,1982,12(1):101–109.
[8]MIN D,MINGSHU T.Formation and expansion of ettringite crystals[J].Cem Concr Res,1994,24(1):119–126.
[9]RAMACHANDRAN V S,SEREDA P J,FELDMAN R F.Mechanism of hydration of calcium oxide[J].Nature,1964,201(4916):288–289.
[10]KUD?ACZ K,RODRIGUEZ-NAVARRO C.The mechanism of vapor phase hydration of calcium oxide:Implications for CO2 capture[J].Environ Sci Technol,2014,48(20):12411–12418.
[11]SERAFEIMIDIS K,ANAGNOSTOU G.On the time-development of sulphate hydration in anhydritic swelling rocks[J].Rock Mech Rock Eng,2013,46(3):619–634.
[12]KOKUBU,M.Use of expansive components for concrete in Japan.ACI Special Publication,1973,38:353–378.
[13]赵顺增,刘立,武旭南,等.HCSA高性能混凝土膨胀剂及其应用[J].膨胀剂与膨胀混凝土,2012,4:7–11.ZHAO Shunzeng,LIU Li,WU Xunan,et al.Expansive Agent Expansive Concr(in Chinese),2012(4):7–11.
[14]OZAWA M,SUHARA K,MORIMOTO H.Expansion energy and hydration products of expansive mortar at different temperatures[C],International Conference on Sustainable Construction Materials&Technologies,2013:1–10.
[15]CHAUNSALI P,MONDAL P.Influence of mineral admixtures on early-age behavior of calcium sulfoaluminate cement[J].ACI Mater J,2015,112(1):1–10.
[16]SHI H,ZHAO Y,LI W.Effects of temperature on the hydration characteristics of free lime[J].Cem Concr Res,2002,32(5):789–793.
[17]AZAM S.Study on the geological and engineering aspects of anhydrite/gypsum transition in the Arabian Gulf coastal deposits[J].Bull Eng Geol Environ,2007,66(2):177–185.
[18]BALONIS M,GLASSER F P.The density of cement phases[J].Cem Concr Res,2009,39(9):733–739.
[19]TELESCA A,MARROCCOLI M,PACE M L,et al.A hydration study of various calcium sulfoaluminate cements[J].Cem Concr Compos,2014,53:224–232.
[20]OGAWA K,ROY D M.C4A3$hydration,ettringite formation,and its expansion mechanism:III.Effect of Ca O,Na OH and Na Cl;conclusions[J].Cem Concr Res,1982,12(2):247–256.
[21]STEIGER M.Crystal growth in porous materials-I:the crystallization pressure of large crystals.J Cryst Growth,2005,282(3):455–469.
[22]BIZZOZERO J,GOSSELIN C,SCRIVENER K L.Expansion mechanisms in calcium aluminate and sulfoaluminate systems with calcium sulfate[J].Cem Concr Res.2014,56:190–202.
[23]MEHTA P K,KLEIN A.Investigations on the hydration products in the system 4Ca O-3Al2O3-SO3-Ca SO4-Ca O-H2O[J].Highway Res Board Special Report,1966,90:32–352.
[24]WINNEFELD F,LOTHENBACH B.Hydration of calcium sulfoaluminate cements—experimental findings and thermodynamic modelling[J].Cem Concr Res,2010,40(8):1239–1247.
[25]CHATTERJI S.Mechanism of expansion of concrete due to the presence of dead-burnt Ca O and Mg O[J].Cem Concr Res,1995,25(1):51–56.
[26]CHAUNSALI P,MONDAL P.Influence of mineral admixtures on early-age behavior of calcium sulfoaluminate cement[J].ACI Mater J,2015,112(1):1–10.
[27]MEHTA P K.Expansion characteristics of calcium sulfoaluminate hydrates[J].J Am Ceram Soc,1967,50(4):204–208.
[2]KLEIN A,TROXELL G E.Studies of calcium sulfoaluminate admixtures for expansive cements[C].ASTM Proceedings,1958,58:968–1008.
[3]KLEIN A,KARBY T,POLIVKA M.Properties of an expansive cement for chemical prestressing[C].ACI J Proceedings ACI,1961,58(7):59–82.
[4]MEHTA P K.Expansion characteristics of calcium sulfoaluminate hydrates[J].J Am Ceram Soc,1967,50(4):204–208.
[5]MEHTA P K.Mechanism of expansion associated with ettringite formation[J].Cem Concr Res,1973,3(1):1–6.
[6]OGAWA K,ROY D M.C4A3$hydration ettringite formation,and itsexpansion mechanism:I.expansion;Ettringite stability[J].Cem Concr Res,1981,11(5/6):741–750.
[7]OGAWA K,ROY D M.C4A3$hydration,ettringite formation,and its expansion mechanism:II.Microstructural observation of expansion[J].Cem Concr Res,1982,12(1):101–109.
[8]MIN D,MINGSHU T.Formation and expansion of ettringite crystals[J].Cem Concr Res,1994,24(1):119–126.
[9]RAMACHANDRAN V S,SEREDA P J,FELDMAN R F.Mechanism of hydration of calcium oxide[J].Nature,1964,201(4916):288–289.
[10]KUD?ACZ K,RODRIGUEZ-NAVARRO C.The mechanism of vapor phase hydration of calcium oxide:Implications for CO2 capture[J].Environ Sci Technol,2014,48(20):12411–12418.
[11]SERAFEIMIDIS K,ANAGNOSTOU G.On the time-development of sulphate hydration in anhydritic swelling rocks[J].Rock Mech Rock Eng,2013,46(3):619–634.
[12]KOKUBU,M.Use of expansive components for concrete in Japan.ACI Special Publication,1973,38:353–378.
[13]赵顺增,刘立,武旭南,等.HCSA高性能混凝土膨胀剂及其应用[J].膨胀剂与膨胀混凝土,2012,4:7–11.ZHAO Shunzeng,LIU Li,WU Xunan,et al.Expansive Agent Expansive Concr(in Chinese),2012(4):7–11.
[14]OZAWA M,SUHARA K,MORIMOTO H.Expansion energy and hydration products of expansive mortar at different temperatures[C],International Conference on Sustainable Construction Materials&Technologies,2013:1–10.
[15]CHAUNSALI P,MONDAL P.Influence of mineral admixtures on early-age behavior of calcium sulfoaluminate cement[J].ACI Mater J,2015,112(1):1–10.
[16]SHI H,ZHAO Y,LI W.Effects of temperature on the hydration characteristics of free lime[J].Cem Concr Res,2002,32(5):789–793.
[17]AZAM S.Study on the geological and engineering aspects of anhydrite/gypsum transition in the Arabian Gulf coastal deposits[J].Bull Eng Geol Environ,2007,66(2):177–185.
[18]BALONIS M,GLASSER F P.The density of cement phases[J].Cem Concr Res,2009,39(9):733–739.
[19]TELESCA A,MARROCCOLI M,PACE M L,et al.A hydration study of various calcium sulfoaluminate cements[J].Cem Concr Compos,2014,53:224–232.
[20]OGAWA K,ROY D M.C4A3$hydration,ettringite formation,and its expansion mechanism:III.Effect of Ca O,Na OH and Na Cl;conclusions[J].Cem Concr Res,1982,12(2):247–256.
[21]STEIGER M.Crystal growth in porous materials-I:the crystallization pressure of large crystals.J Cryst Growth,2005,282(3):455–469.
[22]BIZZOZERO J,GOSSELIN C,SCRIVENER K L.Expansion mechanisms in calcium aluminate and sulfoaluminate systems with calcium sulfate[J].Cem Concr Res.2014,56:190–202.
[23]MEHTA P K,KLEIN A.Investigations on the hydration products in the system 4Ca O-3Al2O3-SO3-Ca SO4-Ca O-H2O[J].Highway Res Board Special Report,1966,90:32–352.
[24]WINNEFELD F,LOTHENBACH B.Hydration of calcium sulfoaluminate cements—experimental findings and thermodynamic modelling[J].Cem Concr Res,2010,40(8):1239–1247.
[25]CHATTERJI S.Mechanism of expansion of concrete due to the presence of dead-burnt Ca O and Mg O[J].Cem Concr Res,1995,25(1):51–56.
[26]CHAUNSALI P,MONDAL P.Influence of mineral admixtures on early-age behavior of calcium sulfoaluminate cement[J].ACI Mater J,2015,112(1):1–10.
[27]MEHTA P K.Expansion characteristics of calcium sulfoaluminate hydrates[J].J Am Ceram Soc,1967,50(4):204–208.