C-(A)-S-H对氯离子的吸附性能研究
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摘要
通过化学沉淀法合成了不同钙硅比(n_(Ca)/n_(Si)=0.8～2.0)和不同铝硅比(n_(Al)/n_(Si)=0～0.6)的水化硅酸钙(C-S-H)和水化硅铝酸钙(C-A-S-H),并以氯盐溶液浸泡结合离子色谱仪(IC)研究了这2种水化产物对氯离子的吸附特性;同时结合傅里叶红外光谱法(FTIR)和扫描电镜(SEM)研究了钙硅比、铝硅比对C-(A)-S-H结构及其微观形貌的影响.结果表明:随着浸泡液浓度的增大,C-S-H和C-A-S-H对氯离子的吸附量均逐渐增大,吸附曲线符合Freundlich吸附模型;钙硅比和铝硅比影响着C-(A)-S-H的聚合度和结构,C-(A)-S-H的氯离子吸附能力随钙硅比有先升高后降低的趋势;随着铝硅比的增大,尤其是铝硅比超过0.2之后,C-A-S-H吸附氯离子的能力明显降低.
Hydrated calcium silicate(C-S-H)and hydrated calcium aluminosilicate(C-A-S-H) with different calcium-silicon ratio(n_(Ca)/n_(Si)=0.8-2.0) and aluminum-silicon ratio(n_(Al)/n_(Si)=0-0.6) were synthesized by chemical precipitation method, and the adsorption capacity of chloride ions were studied by ion chromatography(IC) after immersion in chloride solution. The effects of calcium-silicon ratio and aluminum-silicon ratio on C-(A)-S-H structure and microscopic morphology were studied by Fourier transform infrared spectroscopy(FTIR) and scanning electron microscopy(SEM). The results show that the adsorption capacity of chloride are increased with the increase of the concentration of chloride solution, which conform to Freundlich adsorption model. Both calcium-silicon ratio and aluminum-silicon ratio affect the polymerization degree and structure of C-(A)-S-H. Chloride adsorption capacity of C-(A)-S-H increases first and then decreases with calcium-silicon ratio. With the increase of aluminum-silicon ratio, especially beyond 0.2, chloride adsorption capacity of C-(A)-S-H decreases significantly.
Hydrated calcium silicate(C-S-H)and hydrated calcium aluminosilicate(C-A-S-H) with different calcium-silicon ratio(n_(Ca)/n_(Si)=0.8-2.0) and aluminum-silicon ratio(n_(Al)/n_(Si)=0-0.6) were synthesized by chemical precipitation method, and the adsorption capacity of chloride ions were studied by ion chromatography(IC) after immersion in chloride solution. The effects of calcium-silicon ratio and aluminum-silicon ratio on C-(A)-S-H structure and microscopic morphology were studied by Fourier transform infrared spectroscopy(FTIR) and scanning electron microscopy(SEM). The results show that the adsorption capacity of chloride are increased with the increase of the concentration of chloride solution, which conform to Freundlich adsorption model. Both calcium-silicon ratio and aluminum-silicon ratio affect the polymerization degree and structure of C-(A)-S-H. Chloride adsorption capacity of C-(A)-S-H increases first and then decreases with calcium-silicon ratio. With the increase of aluminum-silicon ratio, especially beyond 0.2, chloride adsorption capacity of C-(A)-S-H decreases significantly.
引文
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[21] PUERTAS F,PALACIOS M,MANZANO H,et al.A model for the C-A-S-H gel formed in alkali-activated slag cements[J].Journal of the European Ceramic Society,2011,31(12):2043-2056.
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[23] 勾密峰,管学茂,孙倩.水化硅酸钙对氯离子的吸附[J].建筑材料学报,2015,18(3):363-368.GOU Mifeng,GUAN Xuemao,SUN Qian.Adsorption of chloride ion by calcium silicate hydrate[J].Journal of Building Materials,2015,18(3):363-368.(in Chinese)
[24] LODEIRO I G,FERNáNDEZ-JIMéNEZ A,PALOMO A,et al.Effect on fresh C-S-H gels of the simultaneous addition of alkali and aluminium[J].Cement and Concrete Research,2010,40(1):27-32.
[2] MOHAMMED T U,HAMADA H.Relationship between free chloride and total chloride contents in concrete[J].Cement and Concrete Research,2003,33(9):1487-1490.
[3] SURYAVANSHI A K,SCANTLEBURY J D,LYON S B.Mechanism of Friedel's salt formation in cements rich in tri-calcium aluminate[J].Cement and Concrete Research,1996,26(5):717-727.
[4] YUAN Q,SHI C,SCHUTTER G D,et al.Chloride binding of cement-based materials subjected to external chloride environment-A review[J].Construction and Building Materials,2009,23(1):1-13.
[5] GLASS G K,BUENFELD N R.The influence of chloride binding on the chloride induced corrosion risk in reinforced concrete[J].Corrosion Science,2000,42(2):329-344.
[6] FLOREA M V A,BROUWERS H J H.Chloride binding related to hydration products:Part I:Ordinary Portland cement[J].Cement and Concrete Research,2012,42(2):282-290.
[7] LARSEN C K.Chloride binding in concrete-effect of surrounding environment and concrete composition[D].Norway:The Norwegian University of Science and Technology,1998.
[8] 余红发,翁智财,孙伟,等.矿渣掺量对混凝土氯离子结合能力的影响[J].硅酸盐学报,2007,35(6):801-806.YU Hongfa,WENG Zhicai,SUN Wei,et al.Influences of slag concrete on chlorine ion binding capacity of concrete[J].Journal of the Chinese Ceramic Society,2007,35(6):801-806.(in Chinese)
[9] 金祖权,孙伟,李秋义,等.矿物掺合料对海水中氯离子的结合能力[J].腐蚀与防护,2009(12):869-873.JIN Zuquan,SUN Wei,LI Qiuyi,et al.Bonding performance ofmineral admixture to chloride in sea water[J].Corrosion and Protection,2009(12):869-873.(in Chinese)
[10] LHOPITAL E,LOTHENBACH B,SCRIVENER K,et al.Alkali uptake in calcium alumina silicate hydrate(C-A-S-H)[J].Cement and Concrete Research,2016,85:122-136.
[11] 罗睿,蔡跃波,王昌义.磨细矿渣净浆和砂浆结合外渗氯离子的性能[J].建筑材料学报,2001,4(2):148-153.LUO Rui,CAI Yuebo,WANG Changyi.Binding capability of chloride ions in mortar and pastewith ground granulated blast furnace slag[J].Journal of Building Materials,2001,4(2):148-153.(in Chinese)
[12] ISMAIL I,BERNAL S A,PROVIS J L.Influence of fly ash on the water and chloride permeability of alkali-activated slag mortars and concretes[J].Construction and Building Materials,2013,48(11):1187-1201.
[13] ZIBARAH,HOOTON R D,THOMAS M D A,et al.Influence of the C/S and C/A ratios of hydration products on the chloride ion binding capacity of lime-SF and lime-MK mixtures[J].Cement and Concrete Research,2008,38(3):422-426.
[14] TANG L,NILSSON L O.Chloride binding capacity and binding isotherms of OPC pastes and mortars[J].Cement and Concrete Research,1993,23(2):247-253.
[15] 勾密峰,管学茂.水泥基材料固化氯离子的研究现状与展望[J].材料导报,2010,24(6):124-127.GOU Mifeng,GUAN Xuemao.A review of chloride binding in cement-based materials[J].Journal of Materials Review,2010,24(6):124-127.(in Chinese)
[16] 张建明.铝掺杂的水化硅酸钙结构及微观形貌研究[D].武汉:武汉理工大学,2011.ZHANG Jianming.Structure and morphology of aluminum substituted calcium silicate hydrate[D].Wuhan:Wuhan University of Technology,2011.(in Chinese)
[17] 翁智财,余红发,孙伟,等.水灰比与水泥用量对混凝土Cl-结合能力的影响[J].武汉理工大学学报.2006,28(3):47-50.WENG Zhicai,YU Hongfa,SUN Wei,et al.Influence of water-cement ratio and cement content onchloride binding capacity of concrete[J].Journal of Wuhan University of Technology,2006,28(3):47-50.(in Chinese)
[18] LOTHENBACH B,NONAT A.Calcium silicate hydrates:Solid and liquid phase composition[J].Cement and Concrete Research,2015,78:57-70.
[19] ROSSEN J E,SCRIVENER K L.Optimization of SEM-EDS to determine the C-A-S-H composition inmatured cement paste samples[J].Materials Characterization,2017,123:294-306.
[20] 杨南如.C-S-H凝胶及其研究方法[J].硅酸盐通报,2003,22(2):46-52.YANG Nanru.C-S-H gel and its determination methods[J].Bulletin of the Chinese Ceramic Society,2003,22(2):46-52.(in Chinese)
[21] PUERTAS F,PALACIOS M,MANZANO H,et al.A model for the C-A-S-H gel formed in alkali-activated slag cements[J].Journal of the European Ceramic Society,2011,31(12):2043-2056.
[22] RICHARDSON I G.Model structures for C-(A)-S-H(I)[J].Acta Crystallographica,2014,B70:903-923.
[23] 勾密峰,管学茂,孙倩.水化硅酸钙对氯离子的吸附[J].建筑材料学报,2015,18(3):363-368.GOU Mifeng,GUAN Xuemao,SUN Qian.Adsorption of chloride ion by calcium silicate hydrate[J].Journal of Building Materials,2015,18(3):363-368.(in Chinese)
[24] LODEIRO I G,FERNáNDEZ-JIMéNEZ A,PALOMO A,et al.Effect on fresh C-S-H gels of the simultaneous addition of alkali and aluminium[J].Cement and Concrete Research,2010,40(1):27-32.