硫酸盐侵蚀下石膏的形成及破坏机制研究现状
|
摘要
硫酸盐侵蚀是影响水泥基材料耐久性的重要因素,它不仅会缩短材料的服役寿命,甚至可能危及结构安全。在硫酸盐侵蚀过程中,钙矾石、石膏和碳硫硅钙石等侵蚀产物不断形成,从而导致材料出现膨胀、开裂、软化和剥落等不同形式的破坏。由于不同侵蚀产物的形成条件和对水泥基材料的侵蚀机理存在明显差异,而侵蚀机理是工程实践中指导预防硫酸盐侵蚀的重要依据,因此探明不同侵蚀产物的形成及稳定条件以及各侵蚀产物对材料的作用机理成为该研究课题的主要内容。从现有研究来看,钙矾石型硫酸盐侵蚀是目前研究最为成熟的一种硫酸盐侵蚀。钙矾石是在高碱性硫酸盐溶液条件下形成的主要侵蚀产物,并且当其在狭小封闭的孔洞中生长时会导致材料发生膨胀、开裂破坏,相应的膨胀机理有吸水肿胀理论、结晶压理论和固相反应理论等。另外,在钙矾石型硫酸盐侵蚀的预防方面,发现通过控制水泥中铝酸三钙含量可有效减小因钙矾石形成而造成的膨胀危害。近年来,世界各地的研究者竞相报道了碳硫硅钙石的形成对混凝土结构造成严重破坏的工程实例,这使得碳硫硅钙石型硫酸盐侵蚀也逐渐受到重视。目前普遍认为碳硫硅钙石的形成主要导致材料出现泥化和分解现象,但其形成条件较为复杂,只在一些特殊环境下才有可能发生。石膏是水泥基材料在硫酸盐侵蚀下形成的另一种较为常见的腐蚀产物,它的形成同样影响着水泥基材料的耐久性能。研究发现,硫酸盐溶液浓度越高,越利于形成石膏,但后来发现溶液pH值对石膏的形成及稳定影响更为显著,同时溶液温度、离子种类以及腐蚀制度等对石膏的形成也有一定影响。由于石膏的化学组成相对简单且不含铝相,因此采用普通抗硫酸盐侵蚀方法并不能有效抑制石膏的形成及破坏。石膏的形成往往伴随着水化产物的溶解脱钙,从而导致材料出现软化和剥落现象,但在石膏的膨胀问题上仍存在较大争议。本文综述了硫酸盐侵蚀下水泥混凝土中石膏形成的影响因素,总结了石膏的生长位置及其引起的脱钙作用,最后对石膏的膨胀作用进行了相关探讨。
Sulfate attack is a pivotal factor affecting the durability of cement-based materials,which will not only shortens the service life of the materials,but may even threaten the safety of the structure.During the process of sulfate attack,erosive products,including ettringite,gypsum,and thaumasite are continuously formed,resulting in various forms of damage such as expansion,cracking,softening,and spalling of the material.Since the formation conditions of diverse erosion products as well as the erosion mechanisms of cement-based materials are significantly different,wherein the erosion mechanism is a crucial basis for guiding the prevention of sulfate attack in engineering practice.Therefore,the formation and stability conditions of diverse erosion products and the corresponding erosion mechanism have become the focus of this project.The ettringite form of sulfate attack is well studied and established in the existing researches.The ettringite is considered as the main erosion product formed under the high alkaline condition,and when it grows in micro pores,expansion even cracks will occur in materials.The corresponding expansion mechanisms include water swelling theory,crystallization pressure theory and solid-state reaction theory.In addition,the research on the prevention of ettringite form of sulfate attack indicated that the expansion caused by ettringite can be controlled effectively by reducing the contents of tricalcium aluminate in cement.In recent years,serious damage to concrete structures caused by the formation of thaumasite has been reported in many countries.Therefore,the thaumasite form of sulfate attack has aroused increasing attention.Currently,it is generally believed that the formation of thaumasite mainly leads to the mudification and decomposition of material,but the formation conditions are relatively complex and only happen in some harsh environments.Gypsum is another common corrosion product of cement-based materials formed by sulfate attack,and its formation impacts on the durability of cement-based materials as well.The studies demonstrate that the high concentration of the sulfate solution contributes to the better formation of gypsum,yet later find that the pH value of the solution remarkably affects the formation and stability of gypsum,while the solution temperature,ion species and immersion regime have a certain impact on the formation of gypsum as well.Due to the chemical composition of gypsum is relatively simple and does not contain aluminum phase,the utilization of a common anti-sulfate attack method does not effectively suppress the formation and deterioration of gypsum.The formation of gypsum is often accompanied by dissolution and decalcification of the hydration products,which leads to softening and detaching of the material,but there is still considerable controversy over the issue of gypsum expansion.In this paper,the influencing factors of the formation of gypsum in concrete under sulfate attack are reviewed,and its growth position and decalcification caused by gypsum are summarized.Finally,the expansion of gypsum is discussed as well.
Sulfate attack is a pivotal factor affecting the durability of cement-based materials,which will not only shortens the service life of the materials,but may even threaten the safety of the structure.During the process of sulfate attack,erosive products,including ettringite,gypsum,and thaumasite are continuously formed,resulting in various forms of damage such as expansion,cracking,softening,and spalling of the material.Since the formation conditions of diverse erosion products as well as the erosion mechanisms of cement-based materials are significantly different,wherein the erosion mechanism is a crucial basis for guiding the prevention of sulfate attack in engineering practice.Therefore,the formation and stability conditions of diverse erosion products and the corresponding erosion mechanism have become the focus of this project.The ettringite form of sulfate attack is well studied and established in the existing researches.The ettringite is considered as the main erosion product formed under the high alkaline condition,and when it grows in micro pores,expansion even cracks will occur in materials.The corresponding expansion mechanisms include water swelling theory,crystallization pressure theory and solid-state reaction theory.In addition,the research on the prevention of ettringite form of sulfate attack indicated that the expansion caused by ettringite can be controlled effectively by reducing the contents of tricalcium aluminate in cement.In recent years,serious damage to concrete structures caused by the formation of thaumasite has been reported in many countries.Therefore,the thaumasite form of sulfate attack has aroused increasing attention.Currently,it is generally believed that the formation of thaumasite mainly leads to the mudification and decomposition of material,but the formation conditions are relatively complex and only happen in some harsh environments.Gypsum is another common corrosion product of cement-based materials formed by sulfate attack,and its formation impacts on the durability of cement-based materials as well.The studies demonstrate that the high concentration of the sulfate solution contributes to the better formation of gypsum,yet later find that the pH value of the solution remarkably affects the formation and stability of gypsum,while the solution temperature,ion species and immersion regime have a certain impact on the formation of gypsum as well.Due to the chemical composition of gypsum is relatively simple and does not contain aluminum phase,the utilization of a common anti-sulfate attack method does not effectively suppress the formation and deterioration of gypsum.The formation of gypsum is often accompanied by dissolution and decalcification of the hydration products,which leads to softening and detaching of the material,but there is still considerable controversy over the issue of gypsum expansion.In this paper,the influencing factors of the formation of gypsum in concrete under sulfate attack are reviewed,and its growth position and decalcification caused by gypsum are summarized.Finally,the expansion of gypsum is discussed as well.
引文
1 Mehta P K,Mehta P K.Mechanism of expansion associated with ettringite formation[J].Cement&Concrete Research,1973,3(1):1.
2 Hansen W C.A discussion of the paper“Mechanism of expansion associated with ettringite formation”by Mehta P K[J].Cement&Concrete Research,1973,3(5):655.
3 Mehta P K.Scanning electron micrographic studies of ettringite formation[J].Cement&Concrete Research,1976,6(2):169.
4 Hansen W C.A discussion of the paper‘Scanning electron microscopic studies of ettringite formation’by Mehta P K[J].Cement&Concrete Research,1976,6(4):595.
5 Ogawa K,Roy D M.C4A3Shydration ettringite formation,and its expansion mechanism:Ⅰ.expansion;Ettringite stability[J].Cement&Concrete Research,1981,11(5-6):741.
6 Xue Jungan.Disscussion on expansion of ettringite phase formation[J].Journal of the Chinese Ceramic Society,1984(2):123(in Chinese).薛君玕.论形成钙矾石相的膨胀[J].硅酸盐学报,1984(2):123.
7 Damidot D,Atkins M,Kindness A,et al.Sulphate attack on concrete:Limits of the AFt stability domain[J].Cement&Concrete Research,1992,22(2-3):229.
8 Min D,Tang M.Formation and expansion of ettringite crystals[J].Cement&Concrete Research,1994,24(1):119.
9 Crammond N.The occurrence of thaumasite in modern construction—A review[J].Cement&Concrete Composites,2002,24:393.
10 Crammond N J.The thaumasite form of sulfate attack in the UK[J].Cement&Concrete Composites,2003,25(8):809.
11 Hobbs D W,Taylor M G.Nature of the thaumasite sulfate attack mechanism in field concrete[J].Cement&Concrete Research,2000,30(4):529.
12 Hu Mingyu,Tang Mingshu.A summary of the research on thaumasite form of sulfate attack[J].Concrete,2004(6):17(in Chinese).胡明玉,唐明述.碳硫硅钙石型硫酸盐腐蚀研究综述[J].混凝土,2004(6):17.
13 Bellmann F,Stark J.Prevention of thaumasite formation in concrete exposed to sulphate attack[J].Cement&Concrete Research,2007,37(8):1215.
14 Pipilikaki P,et al.The effect of temperature on thaumasite formation[J].Cement&Concrete Composites,2008,30(10):964.
15 Rendell F,Jauberthie R,Camps J P.The effect of surface gypsum deposits on the durability of cementitious mortars under sulfate attack[J].Concrete Science and Engineering,2000,2:32.
16 Santhanam M,Cohen M D,Olek J.Sulfate attack research—whither now?[J].Cement&Concrete Research,2001,31(6):845.
17 González M A,Irassar E F.Ettringite formation in low C3A Portland cement exposed to sodium sulfate solution[J].Cement&Concrete Research,1997,27(7):1061.
18 Tian B.Microanalytical and microstructural studies on the mechanism of sulfate attack[D].West Lafayette:Purdue University,1998.
19 Santhanam M,Cohen M D,Olek J.Modeling the effects of solution temperature and concentration during sulfate attack on cement mortars[J].Cement&Concrete Research,2002,32(4):585.
20 Lee S T,Moon H Y,Hooton R D,et al.Effect of solution concentrations and replacement levels of metakaolin on the resistance of mortars exposed to magnesium sulfate solutions[J].Cement&Concrete Research,2005,35(7):1314.
21 Dehwah H A F.Effect of sulfate concentration and associated cation type on concrete deterioration and morphological changes in cement hydrates[J].Construction&Building Materials,2007,21(1):29.
22 Lee S T.Performance of mortars exposed to different sulfate concentrations[J].Ksce Journal of Civil Engineering,2012,16(4):601.
23 Santhanam M.Studies on sulfate attack:Mechanisms,test methods,and modeling[D].West Lafayette:Purdue University,2001.
24 Yang Nanru,Zhong Baiqian,Dong Pan,et al.The condition of formation and stability for ettringite[J].Journal of the Chinese Ceramic Society,1984(2):27(in Chinese).杨南如,钟白茜,董攀,等.钙矾石的形成和稳定条件[J].硅酸盐学报,1984(2):27.
25 Neville A.The confused world of sulfate attack on concrete[J].Cement&Concrete Research,2004,34(8):1275.
26 Skalny J,Marchand J,Odler I.Sulfate attack on concrete[M].London:Spon Press,2002:1.
27 Schmidt T,Lothenbach B,Romer M,et al.Physical and microstructural aspects of sulfate attack on ordinary and limestone blended Portland cements[J].Cement&Concrete Research,2009,39:1111.
28 Chabrelie A.Mechanisms of degradation of concrete by external sulfate ions under laboratory and field conditions[D].Lay sanne:cole Polytechnique Fédérale de Lausanne,2011.
29 Planel D,Sercombe J,Bescop P L,et al.Long-term performance of cement paste during combined calcium leaching-sulfate attack:Kinetics and size effect[J].Cement&Concrete Research,2006,36:137.
30 Bellmann F,Erfurt W,Ludwig H M.Field performance of concrete exposed to sulphate and low pH conditions from natural and industrial sources[J].Cement&Concrete Composites,2012,34(1):86.
31 Liu K,Mo L,Deng M.Influence of pH on the formation of gypsum in cement materials during sulfate attack[J].Advances in Cement Research,2015,27(8):487.
32 Bellmann F,M9ser B,Stark J.Influence of sulfate solution concentration on the formation of gypsum in sulfate resistance test specimen[J].Cement&Concrete Research,2006,36(2):358.
33 Müllauer W,Robin E,Beddoe,et al.Sulfate attack on concrete-solution concentration and phase stability[C]∥Conference Record of Concrete in Aggressive Aqueous Environments,Performance,Testing and Modeling.Toulouse,France,2009:18.
34 Kunther W,Lothenbach B,Scrivener K L.On the relevance of volume increase for the length changes of mortar bars in sulfate solutions[J].Cement&Concrete Research,2013,46(46):23.
35 Wang X,Pan Z,Shen X,et al.Stability and decomposition mechanism of ettringite in presence of ammonium sulfate solution[J].Construction&Building Materials,2016,124:786.
36 Wang X,Pan Z.Chemical changes and reaction mechanism of hardened cement paste-(NH4)2SO4-H2O system[J].Construction&Building Materials,2017,152:434.
37 Kunther W,Lothenbach B,Scrivener K.Influence of bicarbonate ions on the deterioration of mortar bars in sulfate solutions[J].Cement&Concrete Research,2013,44(1):77.
38 Piasta W.Analysis of carbonate and sulphate attack on concrete structures[J].Engineering Failure Analysis,2017,79:606.
39 Lawrence C D.Sulphate attack on concrete[J].Magazine of Concrete Research,1990,42(153):249.
40 Gao Xiaojian,Ma Baoguo,Luo Zhongtao.Influence of temperature on sulfate attack of cement mortar[J].Journal of Wuhan University of Technology,2006,28(3):32(in Chinese).高小建,马保国,罗忠涛.水泥胶砂硫酸盐侵蚀的温度效应研究[J].武汉理工大学学报,2006,28(3):32.
41 He Miaomiao.The influence of heat sulfate solution to mechanics performance of concrete[D].Chengdu:Southwest Jiaotong University,2016(in Chinese).何苗苗.高热硫酸盐液对混凝土力学性能的影响[D].成都:西南交通大学,2016.
42 Chen F,Gao J,Qi B,et al.Deterioration mechanism of plain and blended cement mortars partially exposed to sulfate attack[J].Construction&Building Materials,2017,154:849.
43 Liu Z,Deng D,Schutter G D,et al.Chemical sulfate attack performance of partially exposed cement and cement+fly ash paste[J].Construction&Building Materials,2012,28(1):230.
44 Nehdi M L,Suleiman A R,Soliman A M.Investigation of concrete exposed to dual sulfate attack[J].Cement&Concrete Research,2014,64:42.
45 Yuan J,Liu Y,Tan Z,et al.Investigating the failure process of concrete under the coupled actions between sulfate attack and dryingwetting cycles by using X-ray CT[J].Construction&Building Materials,2016,108:129.
46 Gao J,Yu Z,Song L,et al.Durability of concrete exposed to sulfate attack under flexural loading and drying-wetting cycles[J].Construction&Building Materials,2013,39(2):33.
47 Liu K,Deng M,Mo L,et al.Deterioration mechanism of Portland cement paste subjected to sodium sulfate attack[J].Advances in Cement Research,2015,27(8):477.
48 Bonen D,Sarkar S L.Replacement of portlandite by gypsum in the interfacial zone related to crystallization pressure[C]∥Proceedings of 95th Annual Meeting,Cement-Based Materials:Present,Future,and Environmental Aspects.Westerville,1993:49.
49 Shen Y,Xu Z,Tang M.The process of sulfate attack on cement mortars[J].Advanced Cement Based Materials,1996,4(1):1.
50 Rozière E,Loukili A,Hachem R E,et al.Durability of concrete exposed to leaching and external sulphate attacks[J].Cement&Concrete Research,2009,39(12):1188.
51 El-Hachem R,et al.Multi-criteria analysis of the mechanism of degradation of Portland cement based mortars exposed to external sulphate attack[J].Cement&Concrete Research,2012,42(10):1327.
52 Scrivener K L,Crumbie A K,Laugesen P.The interfacial transition zone(ITZ)between cement paste and aggregate in concrete[J].Interface Science,2004,12(4):411.
53 Bourdette B,Ringot E,Ollivier J P.Modelling of the transition zone porosity[J].Cement&Concrete Research,1995,25(4):741.
54 Wu K,Shi H,Xu L,et al.Microstructural characterization of ITZ in blended cement concretes and its relation to transport properties[J].Cement&Concrete Research,2016,79:243.
55 Ollivier J P,Maso J C,Bourdette B.Interfacial transition zone in concrete[J].Advanced Cement Based Materials,1995,2(1):30.
56 Elsharief A,Cohen M D,Olek J.Influence of aggregate size,water cement ratio and age on the microstructure of the interfacial transition zone[J].Cement&Concrete Research,2003,33(11):1837.
57 Gollop R S,Taylor H F W.Microstructural and microanalytical studies of sulfate attack.Ⅰ.Ordinary portland cement paste[J].Cement&Concrete Research,1992,22(6):1027.
58 Gollop R S,Taylor H F W.Microstructural and microanalytical studies of sulfate attackⅢ.Sulfate-resisting portland cement:Reactions with sodium and magnesium sulfate solutions[J].Cement&Concrete Research,1995,25(7):1581.
59 Diamond S,Lee R J.Microstructural alterations associated with sulfate attack in permeable concretes.In:Skalny J,Marchand J.Material Science of Concrete-Sulfate Attack Mechanisms[M].Westerville:American Ceramic Society,1999.
60 Santhanam M,Cohen M D,Olek J.Effects of gypsum formation on the performance of cement mortars during external sulfate attack[J].Cement&Concrete Research,2003,33(3):325.
61 Kamali S,Moranville M,Leclercq S.Material and environmental parameter effects on the leaching of cement pastes:Experiments and modelling[J].Cement&Concrete Research,2008,38(4):575.
62 Jain J,Neithalath N.Analysis of calcium leaching behavior of plain and modified cement pastes in pure water[J].Cement&Concrete Composites,2009,31(3):176.
63 Yang H,Jiang L,Zhang Y,et al.Predicting the calcium leaching behavior of cement pastes in aggressive environments[J].Construction&Building Materials,2012,29(4):88.
64 Mller N.The prediction of mineral solubilities in natural waters:A chemical equilibrium model for the Na-Ca-Cl-SO4-H2O system,to high temperature and concentration[J].Geochimica et Cosmochimica Acta,1988,52(4):821.
65 Yu C,Sun W,Scrivener K.Mechanism of expansion of mortars immersed in sodium sulfate solutions[J].Cement&Concrete Research,2013,43(43):105.
66 Bonen D,Cohen M D.Magnesium sulfate attack on portland cement paste—Ⅰ.Microstructural analysis[J].Cement&Concrete Research,1992,22(1):169.
67 Bonen D,Cohen M D.Magnesium sulfate attack on portland cement paste—Ⅱ.Chemical and mineralogical analyses[J].Cement&Concrete Research,1992,22(4):707.
68 Santhanam M,Cohen M D,Olek J.Mechanism of sulfate attack:A fresh look:Part 1:Summary of experimental results[J].Cement&Concrete Research,2002,32(6):915.
69 Santhanam M,Cohen M D,Olek J.Mechanism of sulfate attack:A fresh look:Part 2:Proposed mechanisms[J].Cement&Concrete Research,2003,33(6):341.
70 Whittaker M,Black L.Current knowledge of external sulfate attack[J].Advances in Cement Research,2015,27(9):1.
71 Hansen W C.Attack on portland cement concrete by alkali soil and water—A critical review[J].Highway Research Record,1966,113:1.
72 Mather B.Discussion of“The process of sulfate attack on cement mortars”by Shen Yang,Xu Zhongzi,and Tang Mingshu[J].Advanced Cement Based Materials,1997,5(3-4):109.
73 Feng P,Garboczi E J,Miao C,et al.Microstructural origins of cement paste degradation by external sulfate attack[J].Construction&Building Materials,2015,96:391.
74 Irassar E F,Bonavetti V L,González M.Microstructural study of sulfate attack on ordinary and limestone Portland cements at ambient temperature[J].Cement&Concrete Research,2003,33(1):31.
75 Nielsen J.Investigation of resistance of cement paste to sulfate attack[J].Highway Research Record,1966,113:114.
76 Mehta P K,Pirtz D,Polivka M.Properties of alite cements[J].Cement&Concrete Research,1979,9(4):439.
77 Mehta P K.Sulfate attack on concrete—A critical review[M]∥Skalny J,Marchand J.Material science of concrete—Sulfate attack mechanisms.Westerville:American Ceramic Society,1992.
78 Wang J G.Sulfate attack on hardened cement paste[J].Cement&Concrete Research,1994,24:735.
79 Tian B,Cohen M D.Does gypsum formation during sulfate attack on concrete lead to expansion?[J].Cement&Concrete Research,2000,30(1):117.
80 Ping X,Beaudoin J J.Mechanism of sulphate expansionⅠ.Thermodynamic principle of crystallization pressure[J].Cement&Concrete Research,1992,22(4):631.
81 Ping X,Beaudoin J J.Mechanism of sulphate expansionⅡ.Validation of thermodynamic theory[J].Cement&Concrete Research,1992,22(5):845.
82 Chen J K,Jiang M Q.Long-term evolution of delayed ettringite and gypsum in Portland cement mortars under sulfate erosion[J].Construction&Building Materials,2009,23(2):812.
83 Xiong C,Jiang L,Xu Y,et al.Deterioration of pastes exposed to leaching,external sulfate attack and the dual actions[J].Construction&Building Materials,2016,116:52.
2 Hansen W C.A discussion of the paper“Mechanism of expansion associated with ettringite formation”by Mehta P K[J].Cement&Concrete Research,1973,3(5):655.
3 Mehta P K.Scanning electron micrographic studies of ettringite formation[J].Cement&Concrete Research,1976,6(2):169.
4 Hansen W C.A discussion of the paper‘Scanning electron microscopic studies of ettringite formation’by Mehta P K[J].Cement&Concrete Research,1976,6(4):595.
5 Ogawa K,Roy D M.C4A3Shydration ettringite formation,and its expansion mechanism:Ⅰ.expansion;Ettringite stability[J].Cement&Concrete Research,1981,11(5-6):741.
6 Xue Jungan.Disscussion on expansion of ettringite phase formation[J].Journal of the Chinese Ceramic Society,1984(2):123(in Chinese).薛君玕.论形成钙矾石相的膨胀[J].硅酸盐学报,1984(2):123.
7 Damidot D,Atkins M,Kindness A,et al.Sulphate attack on concrete:Limits of the AFt stability domain[J].Cement&Concrete Research,1992,22(2-3):229.
8 Min D,Tang M.Formation and expansion of ettringite crystals[J].Cement&Concrete Research,1994,24(1):119.
9 Crammond N.The occurrence of thaumasite in modern construction—A review[J].Cement&Concrete Composites,2002,24:393.
10 Crammond N J.The thaumasite form of sulfate attack in the UK[J].Cement&Concrete Composites,2003,25(8):809.
11 Hobbs D W,Taylor M G.Nature of the thaumasite sulfate attack mechanism in field concrete[J].Cement&Concrete Research,2000,30(4):529.
12 Hu Mingyu,Tang Mingshu.A summary of the research on thaumasite form of sulfate attack[J].Concrete,2004(6):17(in Chinese).胡明玉,唐明述.碳硫硅钙石型硫酸盐腐蚀研究综述[J].混凝土,2004(6):17.
13 Bellmann F,Stark J.Prevention of thaumasite formation in concrete exposed to sulphate attack[J].Cement&Concrete Research,2007,37(8):1215.
14 Pipilikaki P,et al.The effect of temperature on thaumasite formation[J].Cement&Concrete Composites,2008,30(10):964.
15 Rendell F,Jauberthie R,Camps J P.The effect of surface gypsum deposits on the durability of cementitious mortars under sulfate attack[J].Concrete Science and Engineering,2000,2:32.
16 Santhanam M,Cohen M D,Olek J.Sulfate attack research—whither now?[J].Cement&Concrete Research,2001,31(6):845.
17 González M A,Irassar E F.Ettringite formation in low C3A Portland cement exposed to sodium sulfate solution[J].Cement&Concrete Research,1997,27(7):1061.
18 Tian B.Microanalytical and microstructural studies on the mechanism of sulfate attack[D].West Lafayette:Purdue University,1998.
19 Santhanam M,Cohen M D,Olek J.Modeling the effects of solution temperature and concentration during sulfate attack on cement mortars[J].Cement&Concrete Research,2002,32(4):585.
20 Lee S T,Moon H Y,Hooton R D,et al.Effect of solution concentrations and replacement levels of metakaolin on the resistance of mortars exposed to magnesium sulfate solutions[J].Cement&Concrete Research,2005,35(7):1314.
21 Dehwah H A F.Effect of sulfate concentration and associated cation type on concrete deterioration and morphological changes in cement hydrates[J].Construction&Building Materials,2007,21(1):29.
22 Lee S T.Performance of mortars exposed to different sulfate concentrations[J].Ksce Journal of Civil Engineering,2012,16(4):601.
23 Santhanam M.Studies on sulfate attack:Mechanisms,test methods,and modeling[D].West Lafayette:Purdue University,2001.
24 Yang Nanru,Zhong Baiqian,Dong Pan,et al.The condition of formation and stability for ettringite[J].Journal of the Chinese Ceramic Society,1984(2):27(in Chinese).杨南如,钟白茜,董攀,等.钙矾石的形成和稳定条件[J].硅酸盐学报,1984(2):27.
25 Neville A.The confused world of sulfate attack on concrete[J].Cement&Concrete Research,2004,34(8):1275.
26 Skalny J,Marchand J,Odler I.Sulfate attack on concrete[M].London:Spon Press,2002:1.
27 Schmidt T,Lothenbach B,Romer M,et al.Physical and microstructural aspects of sulfate attack on ordinary and limestone blended Portland cements[J].Cement&Concrete Research,2009,39:1111.
28 Chabrelie A.Mechanisms of degradation of concrete by external sulfate ions under laboratory and field conditions[D].Lay sanne:cole Polytechnique Fédérale de Lausanne,2011.
29 Planel D,Sercombe J,Bescop P L,et al.Long-term performance of cement paste during combined calcium leaching-sulfate attack:Kinetics and size effect[J].Cement&Concrete Research,2006,36:137.
30 Bellmann F,Erfurt W,Ludwig H M.Field performance of concrete exposed to sulphate and low pH conditions from natural and industrial sources[J].Cement&Concrete Composites,2012,34(1):86.
31 Liu K,Mo L,Deng M.Influence of pH on the formation of gypsum in cement materials during sulfate attack[J].Advances in Cement Research,2015,27(8):487.
32 Bellmann F,M9ser B,Stark J.Influence of sulfate solution concentration on the formation of gypsum in sulfate resistance test specimen[J].Cement&Concrete Research,2006,36(2):358.
33 Müllauer W,Robin E,Beddoe,et al.Sulfate attack on concrete-solution concentration and phase stability[C]∥Conference Record of Concrete in Aggressive Aqueous Environments,Performance,Testing and Modeling.Toulouse,France,2009:18.
34 Kunther W,Lothenbach B,Scrivener K L.On the relevance of volume increase for the length changes of mortar bars in sulfate solutions[J].Cement&Concrete Research,2013,46(46):23.
35 Wang X,Pan Z,Shen X,et al.Stability and decomposition mechanism of ettringite in presence of ammonium sulfate solution[J].Construction&Building Materials,2016,124:786.
36 Wang X,Pan Z.Chemical changes and reaction mechanism of hardened cement paste-(NH4)2SO4-H2O system[J].Construction&Building Materials,2017,152:434.
37 Kunther W,Lothenbach B,Scrivener K.Influence of bicarbonate ions on the deterioration of mortar bars in sulfate solutions[J].Cement&Concrete Research,2013,44(1):77.
38 Piasta W.Analysis of carbonate and sulphate attack on concrete structures[J].Engineering Failure Analysis,2017,79:606.
39 Lawrence C D.Sulphate attack on concrete[J].Magazine of Concrete Research,1990,42(153):249.
40 Gao Xiaojian,Ma Baoguo,Luo Zhongtao.Influence of temperature on sulfate attack of cement mortar[J].Journal of Wuhan University of Technology,2006,28(3):32(in Chinese).高小建,马保国,罗忠涛.水泥胶砂硫酸盐侵蚀的温度效应研究[J].武汉理工大学学报,2006,28(3):32.
41 He Miaomiao.The influence of heat sulfate solution to mechanics performance of concrete[D].Chengdu:Southwest Jiaotong University,2016(in Chinese).何苗苗.高热硫酸盐液对混凝土力学性能的影响[D].成都:西南交通大学,2016.
42 Chen F,Gao J,Qi B,et al.Deterioration mechanism of plain and blended cement mortars partially exposed to sulfate attack[J].Construction&Building Materials,2017,154:849.
43 Liu Z,Deng D,Schutter G D,et al.Chemical sulfate attack performance of partially exposed cement and cement+fly ash paste[J].Construction&Building Materials,2012,28(1):230.
44 Nehdi M L,Suleiman A R,Soliman A M.Investigation of concrete exposed to dual sulfate attack[J].Cement&Concrete Research,2014,64:42.
45 Yuan J,Liu Y,Tan Z,et al.Investigating the failure process of concrete under the coupled actions between sulfate attack and dryingwetting cycles by using X-ray CT[J].Construction&Building Materials,2016,108:129.
46 Gao J,Yu Z,Song L,et al.Durability of concrete exposed to sulfate attack under flexural loading and drying-wetting cycles[J].Construction&Building Materials,2013,39(2):33.
47 Liu K,Deng M,Mo L,et al.Deterioration mechanism of Portland cement paste subjected to sodium sulfate attack[J].Advances in Cement Research,2015,27(8):477.
48 Bonen D,Sarkar S L.Replacement of portlandite by gypsum in the interfacial zone related to crystallization pressure[C]∥Proceedings of 95th Annual Meeting,Cement-Based Materials:Present,Future,and Environmental Aspects.Westerville,1993:49.
49 Shen Y,Xu Z,Tang M.The process of sulfate attack on cement mortars[J].Advanced Cement Based Materials,1996,4(1):1.
50 Rozière E,Loukili A,Hachem R E,et al.Durability of concrete exposed to leaching and external sulphate attacks[J].Cement&Concrete Research,2009,39(12):1188.
51 El-Hachem R,et al.Multi-criteria analysis of the mechanism of degradation of Portland cement based mortars exposed to external sulphate attack[J].Cement&Concrete Research,2012,42(10):1327.
52 Scrivener K L,Crumbie A K,Laugesen P.The interfacial transition zone(ITZ)between cement paste and aggregate in concrete[J].Interface Science,2004,12(4):411.
53 Bourdette B,Ringot E,Ollivier J P.Modelling of the transition zone porosity[J].Cement&Concrete Research,1995,25(4):741.
54 Wu K,Shi H,Xu L,et al.Microstructural characterization of ITZ in blended cement concretes and its relation to transport properties[J].Cement&Concrete Research,2016,79:243.
55 Ollivier J P,Maso J C,Bourdette B.Interfacial transition zone in concrete[J].Advanced Cement Based Materials,1995,2(1):30.
56 Elsharief A,Cohen M D,Olek J.Influence of aggregate size,water cement ratio and age on the microstructure of the interfacial transition zone[J].Cement&Concrete Research,2003,33(11):1837.
57 Gollop R S,Taylor H F W.Microstructural and microanalytical studies of sulfate attack.Ⅰ.Ordinary portland cement paste[J].Cement&Concrete Research,1992,22(6):1027.
58 Gollop R S,Taylor H F W.Microstructural and microanalytical studies of sulfate attackⅢ.Sulfate-resisting portland cement:Reactions with sodium and magnesium sulfate solutions[J].Cement&Concrete Research,1995,25(7):1581.
59 Diamond S,Lee R J.Microstructural alterations associated with sulfate attack in permeable concretes.In:Skalny J,Marchand J.Material Science of Concrete-Sulfate Attack Mechanisms[M].Westerville:American Ceramic Society,1999.
60 Santhanam M,Cohen M D,Olek J.Effects of gypsum formation on the performance of cement mortars during external sulfate attack[J].Cement&Concrete Research,2003,33(3):325.
61 Kamali S,Moranville M,Leclercq S.Material and environmental parameter effects on the leaching of cement pastes:Experiments and modelling[J].Cement&Concrete Research,2008,38(4):575.
62 Jain J,Neithalath N.Analysis of calcium leaching behavior of plain and modified cement pastes in pure water[J].Cement&Concrete Composites,2009,31(3):176.
63 Yang H,Jiang L,Zhang Y,et al.Predicting the calcium leaching behavior of cement pastes in aggressive environments[J].Construction&Building Materials,2012,29(4):88.
64 Mller N.The prediction of mineral solubilities in natural waters:A chemical equilibrium model for the Na-Ca-Cl-SO4-H2O system,to high temperature and concentration[J].Geochimica et Cosmochimica Acta,1988,52(4):821.
65 Yu C,Sun W,Scrivener K.Mechanism of expansion of mortars immersed in sodium sulfate solutions[J].Cement&Concrete Research,2013,43(43):105.
66 Bonen D,Cohen M D.Magnesium sulfate attack on portland cement paste—Ⅰ.Microstructural analysis[J].Cement&Concrete Research,1992,22(1):169.
67 Bonen D,Cohen M D.Magnesium sulfate attack on portland cement paste—Ⅱ.Chemical and mineralogical analyses[J].Cement&Concrete Research,1992,22(4):707.
68 Santhanam M,Cohen M D,Olek J.Mechanism of sulfate attack:A fresh look:Part 1:Summary of experimental results[J].Cement&Concrete Research,2002,32(6):915.
69 Santhanam M,Cohen M D,Olek J.Mechanism of sulfate attack:A fresh look:Part 2:Proposed mechanisms[J].Cement&Concrete Research,2003,33(6):341.
70 Whittaker M,Black L.Current knowledge of external sulfate attack[J].Advances in Cement Research,2015,27(9):1.
71 Hansen W C.Attack on portland cement concrete by alkali soil and water—A critical review[J].Highway Research Record,1966,113:1.
72 Mather B.Discussion of“The process of sulfate attack on cement mortars”by Shen Yang,Xu Zhongzi,and Tang Mingshu[J].Advanced Cement Based Materials,1997,5(3-4):109.
73 Feng P,Garboczi E J,Miao C,et al.Microstructural origins of cement paste degradation by external sulfate attack[J].Construction&Building Materials,2015,96:391.
74 Irassar E F,Bonavetti V L,González M.Microstructural study of sulfate attack on ordinary and limestone Portland cements at ambient temperature[J].Cement&Concrete Research,2003,33(1):31.
75 Nielsen J.Investigation of resistance of cement paste to sulfate attack[J].Highway Research Record,1966,113:114.
76 Mehta P K,Pirtz D,Polivka M.Properties of alite cements[J].Cement&Concrete Research,1979,9(4):439.
77 Mehta P K.Sulfate attack on concrete—A critical review[M]∥Skalny J,Marchand J.Material science of concrete—Sulfate attack mechanisms.Westerville:American Ceramic Society,1992.
78 Wang J G.Sulfate attack on hardened cement paste[J].Cement&Concrete Research,1994,24:735.
79 Tian B,Cohen M D.Does gypsum formation during sulfate attack on concrete lead to expansion?[J].Cement&Concrete Research,2000,30(1):117.
80 Ping X,Beaudoin J J.Mechanism of sulphate expansionⅠ.Thermodynamic principle of crystallization pressure[J].Cement&Concrete Research,1992,22(4):631.
81 Ping X,Beaudoin J J.Mechanism of sulphate expansionⅡ.Validation of thermodynamic theory[J].Cement&Concrete Research,1992,22(5):845.
82 Chen J K,Jiang M Q.Long-term evolution of delayed ettringite and gypsum in Portland cement mortars under sulfate erosion[J].Construction&Building Materials,2009,23(2):812.
83 Xiong C,Jiang L,Xu Y,et al.Deterioration of pastes exposed to leaching,external sulfate attack and the dual actions[J].Construction&Building Materials,2016,116:52.