Performance Degradation Law of Concretes in the Multi-salt Coupling Corrosion Environment

doi:10.12068/j.issn.1005-3026.2023.04.017

Abstract

Abstract: In order to explore the effect of the actual industrial chemical corrosion environment on the physical and mechanical properties of concretes， the site exposure tests of half immersion and full immersion were adopted in the chlorine， sulfate and magnesium salt environments， and therewith the corresponding corrosion simulation tests were carried out in the laboratory. The effects of different water-binder ratios， different corrosion concentrations and different dry-wet periods on concretes’ quality， compressive strength， dynamic elastic modulus and thickness of the damaged layer were studied. The results showed that the relative mass， relative dynamic elastic modulus and compressive strength of half-immersed concretes and laboratory simulated concretes all increase first and then decrease with time and the thickness of the damaged layer continues to increase with time. The degradation damage of full-immersed concretes is much lower than those by half immersion， and the time required for each turning point by full immersion is prolonged. With the increase of the water-binder ratio， concentration， and shortening of the dry-wet period， it is easier to produce Friedel’s salt， ettringite， and magnesium hydroxide in concretes， and accelerate the deterioration of concretes. The order of corrosive ions infiltrating into concretes is:chloride ions， sulfate ions and magnesium ions.

Key words: chemical corrosion; multi-salt coupling; site exposure; laboratory simulation; relative dynamic elastic modulus

CLC Number:

TU528

HE Sheng， QIN Zhi-di， LI Yu-tao5， YU Peng. Performance Degradation Law of Concretes in the Multi-salt Coupling Corrosion Environment[J]. Journal of Northeastern University(Natural Science), 2023, 44(4): 581-589.

References

[1]Zhao G P，Li J P，Shi M，et al.Degradation of cast-in-situ concrete subjected to sulphate-chloride combined attack［J］.Construction and Building Materials，2020，241:117995.
[2]Du J，Tang Z，Li G，et al.Key inhibitory mechanism of external chloride ions on concrete sulfate attack［J］.Construction and Building Materials，2019，225:611-619.
[3]Zhao G，Li J，Han F，et al.Sulfate-induced degradation of cast-in-situ concrete influenced by magnesium［J］.Construction and Building Materials，2019，199:194-206.
[4]Gopalakrishnan R，Jeyalakshmi R.The effects on durability and mechanical properties of multiple nano and micro additive OPC mortar exposed to combined chloride and sulfate attack［J］.Materials Science in Semiconductor Processing，2020，106:104772.
[5]Wang J，Cai G，Wu Q.Basic mechanical behaviours and deterioration mechanism of RC beams under chloride-sulphate environment［J］.Construction and Building Materials，2018，160:450-461.
[6]Tan Y，Yu H，Ma H，et al.Study on the micro-crack evolution of concrete subjected to stress corrosion and magnesium sulfate［J］.Construction and Building Materials，2017，141:453-460.
[7]王小刚，史才军，何富强，等.氯离子结合及其对水泥基材料微观结构的影响［J］.硅酸盐学报，2013，41(2):187-198.(Wang Xiao-gang，Shi Cai-jun，He Fu-qiang，et al.Chloride binding and its effects on microstructure of cement-based materials［J］.Journal of the Chinese Ceramic Society，2013，41(2):187-198.)
[8]Yue Y，Wang J，Basheer P A M，et al.Raman spectroscopic investigation of Friedel’s salt［J］.Cement and Concrete Composites，2018，86:306-314.
[9]Qiao C，Suraneni P，Weiss J.Damage in cement pastes exposed to NaCl solutions［J］.Construction and Building Materials，2018，171:120-127.
[10]刘琪，冯攀，叶少雄，等.硅酸三钙在含氯离子或镁离子溶液中的溶解动力学行为［J］.硅酸盐学报，2021，49(5):1-11.(Liu Qi，Feng Pan，Ye Shao-xiong，et al.Dissolution kinetics of tricalcium silicate in solution containing chloride or magnesium ions［J］.Journal of the Chinese Ceramic Society，2021，49(5):1-11.)
[11]Santhanam M.Magnesium attack of cementitious materials in marine environments［M］.Dordrecht:Springer Netherlands，2012:75-90.
[12]钱觉时，马英，杨莎，等.硅酸盐水泥中硫酸盐特性及其对混凝土性能的影响［J］.硅酸盐学报，2015，43(10):1430-1440.(Qian Jue-shi，Ma Ying，Yang Sha，et al.Characteristics of sulfates in portland cement and their influence on concrete［J］.Journal of the Chinese Ceramic Society，2015，43(10):1430-1440.)
[13]Yang Z Q，Jiang J Y，Jiang X，et al.The influence of sodium sulfate and magnesium sulfate on the stability of bound chlorides in cement paste［J］.Construction and Building Materials，2019，228:116775.
[14]Yao J，Chen J，Lu C.Entropy evolution during crack propagation in concrete under sulfate attack［J］.Construction and Building Materials，2019，209:492-498.
[15]Haufe J，Vollpracht A.Tensile strength of concrete exposed to sulfate attack［J］.Cement and Concrete Research，2019，116:81-88.
[16]Qiao C，Ni W，Wang Q，et al.Chloride diffusion and wicking in concrete exposed to NaCl and MgCl₂ solutions［J］.Journal of Materials in Civil Engineering，2018，30(3):4018015.
[17]Li C，Wu M，Chen Q，et al.Chemical and mineralogical alterations of concrete subjected to chemical attacks in complex underground tunnel environments during 20-36 years［J］.Cement and Concrete Composites，2018，86:139-159.
[18]Zhang M，Chen J，Lv Y，et al.Study on the expansion of concrete under attack of sulfate and sulfate-chloride ions［J］.Construction and Building Materials，2013，39:26-32.
[19]Irbe L，Beddoe R E，Heinz D.The role of aluminium in C-A-S-H during sulfate attack on concrete［J］.Cement and Concrete Research，2019，116:71-80.
[20]吴凯，施惠生，徐玲琳，等.集料对含矿粉混凝土抗硫酸镁侵蚀性能的影响［J］.建筑材料学报，2016，19(3):442-448.(Wu Kai，Shi Hui-sheng，Xu Ling-lin，et al.Effect of aggregate on degradation of slag blended concrete under magnesium sulfate attack［J］.Journal of Build Materials，2016，19(3):442-448.)
[21]De Weerdt K，Justnes H，Geiker M R.Changes in the phase assemblage of concrete exposed to sea water［J］.Cement and Concrete Composites，2014，47:53-63.
[22]Binici H，Aksogˇan O.Sulfate resistance of plain and blended cement［J］.Cement and Concrete Composites，2006，28:39-46.