多孔壳微胶囊对硬化砂浆抗渗性的影响
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摘要
采用原位聚合与水解缩聚法,以四乙氧基硅烷(TEOS)、环氧树脂(E51)、苯乙烯(St)等为主要原料,合成了一种二氧化硅多孔壳微胶囊(Porous silica shell microcapsules,PSSM)。分别采用SEM、FTIR、TGA对PSSM外观形貌、化学组分、核壳比进行表征。通过对掺加PSSM的砂浆试块进行80%抗压强度荷载预压、养护(浸水或干湿循环养护)处理后,运用交流阻抗法与压汞法研究了PSSM对硬化砂浆抗渗性与孔结构的影响规律。结果表明:制备的PSSM粒径约为10～100μm,其含有聚苯乙烯网络支架、环氧树脂和聚硅氧烷囊芯,支架聚合物和多孔壳,核壳质量比为1.54。与未预压-养护处理的试块相比,经预压-养护处理后的空白试块的连通孔溶液电阻RCH和扩散阻抗系数σ均降低,孔隙率升高,表明预压使试块内形成微裂纹缺陷,经养护仍未愈合,因此试块抗渗性降低;而对于掺加8%PSSM的试块,经预压-养护处理后其RCH和σ均增加,孔隙率降低,表明试块抗渗性提高。这是由于PSSM的破壳-固化作用以及长期浸水或干湿循环养护,导致试块中PSSM发生了渗出-固化作用,封堵愈合了试块内的微裂隙,抗渗性得到提高。
By using tetraethyl orthosilicate(TEOS),epoxide resin(E51),styrene(St),et al.as the main materials,a kind of porous silica shell microcapsules(PSSM)were synthesized through in-polymerization in the core and hydrolysis-polycondensation for forming the shell.Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR)and thermogravimetric analysis(TGA)were used to characterize the morphology,chemical composition and core shell ratio of the synthesized PSSM.Influences of PSSM on the impermeability and pore structure of hardened cement mortar via alternating current impedance spectroscopy technique(ACI)and mercury intrusion porosimetry(MIP)were studied after the hardened cement mortar samples were preloaded by 80%their compressive strength loads and cured including water curing or dry-wet cycling curing.The characterization results prove that the obtained product presents core-shell structured microcapsules with size of 10-100μm,in which polysiloxane forms porous shell and liquid form epoxy resin held by apolystyrene network composes the core.The mass ratio of the core to shell is 1.54.Compare with the blank samples without preloading-curing treatment,connected pore solution resistance RCHand diffusion resistance coefficientσof the preloading-curing treated blank samples decrease and their porosities increase,which suggests that the preloading treatment leads to the formation of microcracks in the specimen and the following curing does not result in full healing of the formed micro-cracks.On the other hand,for those sample containing 8% PSSM,RCH andσof the preloading-curing treated samples are even higher than those of the non-treated samples.This phenomenon is attributed to the micro-cracks formation due to the preloading treatment allows invasion of water into the body of the mortar specimens during the following water immersion.Thus,the PSSM that is incorporated into the mortar samples contributes to crack healing by leakage of the epoxy resin from the core through the intact or broken porous shell and the subsequent curing reaction with the curing agent located in cement matrix.The above mentioned results provide a clear proof of concept for such selfhealing microcapsules.
By using tetraethyl orthosilicate(TEOS),epoxide resin(E51),styrene(St),et al.as the main materials,a kind of porous silica shell microcapsules(PSSM)were synthesized through in-polymerization in the core and hydrolysis-polycondensation for forming the shell.Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR)and thermogravimetric analysis(TGA)were used to characterize the morphology,chemical composition and core shell ratio of the synthesized PSSM.Influences of PSSM on the impermeability and pore structure of hardened cement mortar via alternating current impedance spectroscopy technique(ACI)and mercury intrusion porosimetry(MIP)were studied after the hardened cement mortar samples were preloaded by 80%their compressive strength loads and cured including water curing or dry-wet cycling curing.The characterization results prove that the obtained product presents core-shell structured microcapsules with size of 10-100μm,in which polysiloxane forms porous shell and liquid form epoxy resin held by apolystyrene network composes the core.The mass ratio of the core to shell is 1.54.Compare with the blank samples without preloading-curing treatment,connected pore solution resistance RCHand diffusion resistance coefficientσof the preloading-curing treated blank samples decrease and their porosities increase,which suggests that the preloading treatment leads to the formation of microcracks in the specimen and the following curing does not result in full healing of the formed micro-cracks.On the other hand,for those sample containing 8% PSSM,RCH andσof the preloading-curing treated samples are even higher than those of the non-treated samples.This phenomenon is attributed to the micro-cracks formation due to the preloading treatment allows invasion of water into the body of the mortar specimens during the following water immersion.Thus,the PSSM that is incorporated into the mortar samples contributes to crack healing by leakage of the epoxy resin from the core through the intact or broken porous shell and the subsequent curing reaction with the curing agent located in cement matrix.The above mentioned results provide a clear proof of concept for such selfhealing microcapsules.
引文
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[15]MIGNON A,GRAULUS G-J,SNOECK D,et al.pH-sensitive superabsorbent polymers:A potential candidate material for self-healing concrete[J].Journal of Materials Science,2015,50:970-979.
[16]XIONG W,TANG J N,ZHU G M,et al.A novel capsulebased self-recovery system with a chloride ion trigger[J].Scientific Reports,2015,5:10866.
[17]朱光明,邢峰,何永兴,等.氯离子触发的微胶囊及其制备方法:中国专利:ZL 201410076580.2[P].2015-10-21.ZHU G M,XING F,HE Y X,et al.Chlorine ion-triggered microcapsules and their preparation methods:China Patent,ZL 201410076580.2[P].2015-10-21(in Chinese).
[18]雷强,朱光明,邢锋,等.Cu2+-P(VIm-MMA)壳微胶囊的制备及其化学触发研究[J].高分子学报,2013(8):950-956.LEI Q,ZHU G M,XING F,et al.Preparation and Chemical Trigger of Cu2+-p(VIm-MMA)Complex Microcapsules[J].Acta Polymerica Sinica,2013(8):950-956(in Chinese).
[19]董必钦,王琰帅,丁蔚健,等.水泥基化学自修复微胶囊系统[J].北京工业大学学报,2014,40(8):1168-1173.DONG B Q,WANG Y S,DING W J,et al.Chemical selfhealing microcapsule for cementitious system[J].Journal of Beijing University of Technology,2014,40(8):1168-1173(in Chinese).
[20]张鸣.水泥基材料用微胶囊自修复技术与原理的研究[D].长沙:中南大学,2013.ZHANG M.A study on microcapsule based self-healing method and mechanism for cementitious composites[D].Changsha:Central South University,2013(in Chinese).
[21]VAN TITTELBOOM K,GRUYAERT E,RAHIER H,et al.Influence of mix composition on the extent of autogenous crack healing by continued hydration or calcium carbonate formation[J].Construction and Building Materials,2012,37:349-359.
[22]SISOMPHON K,COPUROGLU O,KOENDERS E A B.Self-healing of surface cracks in mortars with expansive additive and crystalline additive[J].Cement and Concrete Composites,2012,34(4):566-574.
[23]MCCARTER W J,STARRS G,CHRISP T M.Electrical conductivity,diffusion,and permeability of Portland cementbased mortars[J].Cement and Concrete Research,2000,30(9):1395-1400
[24]NEITHALATH N,JAIN J.Relating rapid chloride transport parameters of concretes to microstructural features extracted from electrical impedance[J].Cement and Concrete Research,2010,40(7):1041-1051.
[25]PERRON S,BEAUDOIN J J.Freezing of water in Portland cement paste—An AC impedance spectroscopy study[J].Cement and Concrete Composites,2002,24(5):467-475
[26]Ferrándiz-Mas V,García-Alcocel E.Durability of expanded polystyrene mortars[J].Construction and Building Materials,2013,46:175-182
[27]ZHANG S Y,SHI M L,CHEN Z Y.The AC response of polymer-coated mortar specimens[J].Cement and Concrete Research,2002,32(6):983-987
[28]ZHANG Y R,KONG X M.Influences of superplasticizer,polymer latexes and asphalt emulsions on the pore structure and impermeability of hardened cementitious materials[J].Construction and Building Materials,2014,53:392-402.
[29]GU P,XIE P,FU Y,BEAUDOIN J J.A.C Impedance phenomena in hydration cement systems:frequency dispersion angle and pore size distribution[J].Cement and Concrete Research,1994,24(1):86-88.
[30]CABEZA M,KEDDAM M,NOVOA X R,et al.Impedance spectroscopy to characterize the pore structure during the hardening process of Portland cement paste[J].Electrochimica Acta,2006,51(8):1831-1841.
[31]SANCHEZ I,NOVOA X R,DE VERA G,et al.Microstructural modifications in Portland cement concrete due to forced ionic migration tests:Study by impedance spectroscopy[J]. Cement and Concrete Research,2008,38(7):1015-1025.
[32]TANG S W,CAI X H,HE Z,et al.The review of early hydration of cement-based materials by electrical methods[J].Construction and Building Materials,2017,146:15-29.
[33]中国国家标准化管理委员会.混凝土外加剂:GB 8076—2008[S].北京:中国标准出版社,2008.Standardization Administration of the People’s Republic of China.Concrete admixtures:GB 8076—2008[S].Beijing:China Standards Press,2008(in Chinese).
[34]MCCARTER W J,BROUSSEAU R.The AC response of hardened cement paste[J].Cement and Concrete Research,1990,20(6):891-900.
[35]CABEZA M,MERINO P,MIRANDA A,et al.Impedance spectroscopy study of hardened Portland cement paste[J].Cement and Concrete Research,2002,32(6):881-891.
[36]史美伦,张莹.水泥水化早中期的交流阻抗研究(I)—起始期的交流阻抗响应分析[J].建筑材料学报,2002,5(3):210-214.SHI M L,ZHANG Y.Study of cement hydration in the early and middle periods by AC impedance technique(I)—AC impedance response in initial period[J].Journal of Building Materials,2002,5(3):210-214(in Chinese).
[37]曹楚南.电化学阻抗谱导论[M].北京:科学出版社,2004.CAO C N.Introduction to Electrochemical Impedance Spectroscopy[M].Beijing:Science Press,2004(in Chinese).
[38]吴立朋,阎培渝.水泥基材料氯离子扩散性交流阻抗谱研究方法综述[J].硅酸盐学报,2012,40(5):651-656.WU L P,YAN P Y.Review on AC impedance techniques for chloride diffusivity determination of cement-based materials[J].Journal of the Chinese Ceramic Society,2012,40(5):651-656(in Chinese).
[39]WEI D F,CHATTERJEE I,JONES D A.Evaluation of corrosive degradation in coated steel using alternating current impedance spectroscopy[J].Corrosion,1995,51(2):97-104.
[2]AMBILY P S,UMARANI C,RAVISANLAR K,et al.Studies on ultra-high performance concrete incorporating copper slag as fine aggregate[J].Construction and Building Materials,2015,77(15):233-240.
[3]CHINDAPRASORT P,CHALEE W.Effect of sodium hydroxide concentration on chloride penetration and steel corrosion of fly ash-based geopolymer concrete under marine site[J]. Construction and Building Materials, 2014, 63:303-310.
[4]BASHEER L,KROPP J,CLELAND D J.Assessment of the durability of concrete from its permeation properties:A review[J].Construction and Building Materials,2001,15(2-3):93-103.
[5]李永强,巴明芳,柳俊哲,等.干湿循环作用下水泥基复合材料抗氯离子侵蚀性能及其微观结构变化[J].复合材料学报,2017,34(12):2857-2865.LI Y Q,BA M F,LIU J Z,et al.Resistance to chloride erosion of cement matrix composite materials under dry-wet cycling and their micro-structural change[J].Acta Materiae Compositae Sinica,2017,34(12):2857-2865(in Chinese).
[6]ABRAM A.Autoge neous healing of conerete[J].Concrete,1925,27(2):50.
[7]VIJAY K,MURMU M,DEO S V.Bacteria based self healing concrete-A review[J].Construction and Building Materials,2017,152(15):1008-1014.
[8]SOURADEEP G,DAI P S,WEI K H,et al.Autonomous healing in concrete by bio-based healing agents—A review[J]. Construction and Building Materials,2017,146:419-428.
[9]邢锋,倪卓,汤皎宁,等.自修复混凝土系统的研究进展[J].深圳大学学报理工版,2013,30(5):486-494.XING F,NI Z,YANG J N,et al.State-of-the-art for selfhealing concrete[J].Journal of Shenzhen University Science and Engineering,2013,30(5):486-494(in Chinese).
[10]袁慎芳.结构健康监控[M].北京:国防工业出版社,2007:241-315.YUAN S F.Structural Health Monitoring and Damage Control[M].Beijing:National Defense Industry Press,2007:241-245(in Chinese).
[11]ZHOU B,LIU Y J,LENG J S,et al.A macro-mechanical constitutive model of shape memory alloys[J].Science in China Series G:Physics,Mechanics &Astronomy,2009,52(9):1382-1391.
[12]姚武,钟文慧.混凝土损伤自愈合的机理[J].材料研究学报,2006,20(1):24-28.YAO W,ZANG W H.Mechanism for self-healing of concrete[J].Chinese Journal of Materials Research,2006,20(1):24-28.(in Chinese)
[13]杨红,梁大开,陶宝祺,等.空心光纤在复合材料断裂位置测量中的研究[J].复合材料学报,2001,19(1):122-125.YANG H,LIANG D K,TAO B Q,et al.Research on selfdiagnose of the rupture place using hollow-center optical fiber in composite material[J].Acta Material Composite Sinica,2002,19(1):122-125(in Chinese).
[14]WHITE S R,SOTTOS N R,GEUBELL P H,et al.Autonomic healing of polymer composites[J].Nature,2001,409(1):794-817.
[15]MIGNON A,GRAULUS G-J,SNOECK D,et al.pH-sensitive superabsorbent polymers:A potential candidate material for self-healing concrete[J].Journal of Materials Science,2015,50:970-979.
[16]XIONG W,TANG J N,ZHU G M,et al.A novel capsulebased self-recovery system with a chloride ion trigger[J].Scientific Reports,2015,5:10866.
[17]朱光明,邢峰,何永兴,等.氯离子触发的微胶囊及其制备方法:中国专利:ZL 201410076580.2[P].2015-10-21.ZHU G M,XING F,HE Y X,et al.Chlorine ion-triggered microcapsules and their preparation methods:China Patent,ZL 201410076580.2[P].2015-10-21(in Chinese).
[18]雷强,朱光明,邢锋,等.Cu2+-P(VIm-MMA)壳微胶囊的制备及其化学触发研究[J].高分子学报,2013(8):950-956.LEI Q,ZHU G M,XING F,et al.Preparation and Chemical Trigger of Cu2+-p(VIm-MMA)Complex Microcapsules[J].Acta Polymerica Sinica,2013(8):950-956(in Chinese).
[19]董必钦,王琰帅,丁蔚健,等.水泥基化学自修复微胶囊系统[J].北京工业大学学报,2014,40(8):1168-1173.DONG B Q,WANG Y S,DING W J,et al.Chemical selfhealing microcapsule for cementitious system[J].Journal of Beijing University of Technology,2014,40(8):1168-1173(in Chinese).
[20]张鸣.水泥基材料用微胶囊自修复技术与原理的研究[D].长沙:中南大学,2013.ZHANG M.A study on microcapsule based self-healing method and mechanism for cementitious composites[D].Changsha:Central South University,2013(in Chinese).
[21]VAN TITTELBOOM K,GRUYAERT E,RAHIER H,et al.Influence of mix composition on the extent of autogenous crack healing by continued hydration or calcium carbonate formation[J].Construction and Building Materials,2012,37:349-359.
[22]SISOMPHON K,COPUROGLU O,KOENDERS E A B.Self-healing of surface cracks in mortars with expansive additive and crystalline additive[J].Cement and Concrete Composites,2012,34(4):566-574.
[23]MCCARTER W J,STARRS G,CHRISP T M.Electrical conductivity,diffusion,and permeability of Portland cementbased mortars[J].Cement and Concrete Research,2000,30(9):1395-1400
[24]NEITHALATH N,JAIN J.Relating rapid chloride transport parameters of concretes to microstructural features extracted from electrical impedance[J].Cement and Concrete Research,2010,40(7):1041-1051.
[25]PERRON S,BEAUDOIN J J.Freezing of water in Portland cement paste—An AC impedance spectroscopy study[J].Cement and Concrete Composites,2002,24(5):467-475
[26]Ferrándiz-Mas V,García-Alcocel E.Durability of expanded polystyrene mortars[J].Construction and Building Materials,2013,46:175-182
[27]ZHANG S Y,SHI M L,CHEN Z Y.The AC response of polymer-coated mortar specimens[J].Cement and Concrete Research,2002,32(6):983-987
[28]ZHANG Y R,KONG X M.Influences of superplasticizer,polymer latexes and asphalt emulsions on the pore structure and impermeability of hardened cementitious materials[J].Construction and Building Materials,2014,53:392-402.
[29]GU P,XIE P,FU Y,BEAUDOIN J J.A.C Impedance phenomena in hydration cement systems:frequency dispersion angle and pore size distribution[J].Cement and Concrete Research,1994,24(1):86-88.
[30]CABEZA M,KEDDAM M,NOVOA X R,et al.Impedance spectroscopy to characterize the pore structure during the hardening process of Portland cement paste[J].Electrochimica Acta,2006,51(8):1831-1841.
[31]SANCHEZ I,NOVOA X R,DE VERA G,et al.Microstructural modifications in Portland cement concrete due to forced ionic migration tests:Study by impedance spectroscopy[J]. Cement and Concrete Research,2008,38(7):1015-1025.
[32]TANG S W,CAI X H,HE Z,et al.The review of early hydration of cement-based materials by electrical methods[J].Construction and Building Materials,2017,146:15-29.
[33]中国国家标准化管理委员会.混凝土外加剂:GB 8076—2008[S].北京:中国标准出版社,2008.Standardization Administration of the People’s Republic of China.Concrete admixtures:GB 8076—2008[S].Beijing:China Standards Press,2008(in Chinese).
[34]MCCARTER W J,BROUSSEAU R.The AC response of hardened cement paste[J].Cement and Concrete Research,1990,20(6):891-900.
[35]CABEZA M,MERINO P,MIRANDA A,et al.Impedance spectroscopy study of hardened Portland cement paste[J].Cement and Concrete Research,2002,32(6):881-891.
[36]史美伦,张莹.水泥水化早中期的交流阻抗研究(I)—起始期的交流阻抗响应分析[J].建筑材料学报,2002,5(3):210-214.SHI M L,ZHANG Y.Study of cement hydration in the early and middle periods by AC impedance technique(I)—AC impedance response in initial period[J].Journal of Building Materials,2002,5(3):210-214(in Chinese).
[37]曹楚南.电化学阻抗谱导论[M].北京:科学出版社,2004.CAO C N.Introduction to Electrochemical Impedance Spectroscopy[M].Beijing:Science Press,2004(in Chinese).
[38]吴立朋,阎培渝.水泥基材料氯离子扩散性交流阻抗谱研究方法综述[J].硅酸盐学报,2012,40(5):651-656.WU L P,YAN P Y.Review on AC impedance techniques for chloride diffusivity determination of cement-based materials[J].Journal of the Chinese Ceramic Society,2012,40(5):651-656(in Chinese).
[39]WEI D F,CHATTERJEE I,JONES D A.Evaluation of corrosive degradation in coated steel using alternating current impedance spectroscopy[J].Corrosion,1995,51(2):97-104.