دوام ملات‌های پوششی سیمانی و ژئوپلیمری در شرایط محیطی شبیه‌سازی شده خلیج فارس

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران و محیط‌زیست، دانشگاه صنعتی امیرکبیر، تهران، ایران

چکیده

با توجه به اهمیت روزافزون سازه ­های ساحلی و وجود شرایط محیطی سخت و خورنده در محیط­ های ساحلی، تعمیر و نگهداری این سازه­ ها از اهمیتی بیش از پیش برخوردار شده است. یکی از راه­های تعمیر و نگهداری این قبیل سازه­ ها اجرای لایه­ پوششی محافظ از ملات­ های پوششی است. در حالی‌ که ملات ­های پایه سیمانی به عنوان رایج­ ترین مصالح برای تعمیر و نگهداری سازه­ های آسیب ­دیده شناخته می­ شوند، در سال‌های اخیر با توجه به اهمیت آثار زیست‌محیطی و همچنین در راستای کاهش انرژی مصرفی استفاده از مواد جایگزین سیمان و ملات ­های ژئوپلیمری نیز در معرض توجه قرار گرفته ­اند. در تحقیق پیش­رو خواص مکانیکی و دوام ۶ طرح ملات، شامل ۴ طرح ملات پایه سیمانی با جایگزینی سرباره کوره آهن­ گدازی و دوده ‌سیلیس و ۲ طرح ملات ژئوپلیمری با پایه سرباره کوره آهن­ گدازی و دوده ‌سیلیس که در محیط شبیه­ سازی شده خلیج ‌فارس عمل­ آوری شده ­اند، مقایسه شده است. در این راستا جهت مقایسه خواص مکانیکی از آزمایشات مقاومت فشاری، مقاومت چسبندگی کششی و جمع شدگی و جهت ارزیابی دوام از آزمایشات جذب آب مویینه، نفوذ آب تحت فشار و مهاجرت تسریع ­شده یون­ های کلراید در سنین مختلف استفاده گردید. نتایج به دست آمده نشان می­دهد که ملات‌های پایه سیمانی 3 جزیی که دارای مقادیر بیشتری از مواد جایگزین سیمان هستند، می‌توانند گزینه بهتری نسبت به ملات‌های پایه سیمانی 2 جزیی و ملات­ های تعمیراتی ژئوپلیمری برای تعمیر سازه‌های بتنی آسیب ‌دیده در مناطق ساحلی نظیر سواحل خلیج ­فارس باشند. در بین سایر مخلوط­ ها نیز مخلوط ژئوپلیمری با فعال ­ساز قلیایی پتاسیم هیدروکسید و مخلوط پایه سیمانی با جایگزین 7/5 درصد وزنی دوده ‌سیلیس می­ توانند به عنوان گزینه­ های مناسب جهت ترمیم سازه ­های آسیب ­دیده معرفی گردند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Durability of cement-based and geopolymer coating mortars in the Persian Gulf simulated environment

نویسندگان [English]

  • faramarz moodi
  • salar lashgari
  • pooria dashti
Concrete Technology and Durability Research Center, Faculty of Civil Engineering, Amirkabir University of Technology, Tehran, Iran.
چکیده [English]

Due to the importance of coastal structures and the existence of destructive environmental conditions near the shores, the maintenance of these structures is more important. One of the ways to maintain such structures is to apply a protective coating layer of mortar. While cement-based mortars are known as the most common materials for repairing damaged structures, in recent years, due to the importance of environmental impacts and also in order to reduce energy consumption, geopolymer mortars have been considered an appropriate alternative. Geopolymers are inorganic aluminosilicate compounds in which, instead of cement, a matrix of aluminosilicate materials (pozzolans), activated by alkaline activators, plays the role of cement paste in the mortar. In this research, mechanical properties and durability of 6 mortar mix designs, including four cement-based mortar mixtures containing supplementary cementitious materials (SCMs) and two geopolymer mortar combinations with furnace slag and silica fume that cured in the simulated Persian Gulf environment, have been compared. In this regard, to compare the mechanical properties, compressive strength, tensile strength, and drying shrinkage tests were conducted. Also, the capillary water absorption, water penetration under pressure, and rapid chloride migration tests are performed to evaluate the durability. The results of this study display that ternary cement-based mortar with higher amounts of SCMs is a better choice than binary cement-based mortars and geopolymer repair mortars for repairing damaged concrete structures in coastal areas such as the Persian Gulf coast. Among other mixtures, the geopolymer mixture with potassium hydroxide as an alkaline activator and the cement-based mixture with a replacement of 7.5% by weight of silica fume can be introduced as suitable materials for repairing marine structures.

کلیدواژه‌ها [English]

  • Durability
  • Persian Gulf simulated environment
  • Chloride ions attack
  • Supplementary cementitious materials
  • Geopolymer mortar
[1] P. Ghods, M. Chini, R. Alizadeh, M. Hoseini, M. Shekarchi, A. Ramezanianpour, The effect of different exposure conditions on the chloride diffusion into concrete in the Persian Gulf region, 3th ConMat, 5  (2005).
[2] A. Ramezanianpour, A. Pourkhorshidi, T. Parhizkar, G.A. Raeis, Assessing durability of  concrete marine structures with different cements and pozzolans in tidal region of Persian Gulf environment, International Conference on Coasts, Ports and Marine Structures (ICOPMAS), ports & marine organization, (2005) (in Persian).
[3] A. Hadj-sadok, S. Kenai, L. Courard, A. Darimont, Microstructure and durability of mortars modified with medium active blast furnace slag, Construction & Building Materials, 25(2) (2011) 1018-1025.
[4] X. Shi, N. Xie, K. Fortune, J. Gong, Durability of steel reinforced concrete in chloride environments: An overview, Construction & Building Materials, 30 (2012) 125-138.
[5] R. Duval, E. Kadri, Influence of silica fume on the workability and the compressive strength of high- performance concretes, Cement & concrete research, 28(4) (1998) 533-547.
[6] J. Khatib, J. Hibbert, Selected engineering properties of concrete incorporating slag and metakaolin, Construction & building materials, 19(6) (2005) 460-472.
[7] G. Li, B. Yang, C. Guo, J. Du, X. Wu, Time dependence and service life prediction of chloride resistance of concrete coatings, Construction & Building Materials, 83 (2015) 19-25.
[8] A. Mahmoodi, H. Afshin, H. Hakimzadeh, D. Jalali, Investigation of durability of  reinforcement concrete in severe corrosive marine environment 3rd International Conference on Concrete and Development ,Tehran, 2009.
[9] A. Ramezanianpour, A. Kazemian, M. Nikravan, A. Mahpur, M. Moghadam, Influence of a low-activity slag and silica fume on the fresh properties and durability of high performance self-consolidating concrete, in:  Proceedings of 3rd International Conference on Sustainable Construction Materials and Technologies, 2013.
[10] R. Gado, M. Hebda, M. Łach, J. Mikuła, Alkali activation of waste clay bricks: Influence of the silica modulus, SiO2/Na2O, H2O/Na2O molar ratio, and liquid/solid ratio, Materials, 13(2) (2020) 383.
[11] M. Nawaz, A. Heitor, M. Sivakumar, Geopolymers in construction-recent developments, Construction & Building Materials, 260 (2020) 120472.
[12] A. Hassan, M. Arif, M. Shariq, Mechanical behaviour and microstructural investigation of geopolymer concrete after exposure to elevated temperatures, Arabian Journal for Science Engineering, 45(5) (2020) 3843-3861.
[13] J. Li, P. Sun, J. Li, Y. Lv, H. Ye, L. Shao, D. Du, Synthesis of electrolytic manganese residue-fly ash based geopolymers with high compressive strength, Construction & Building Materials, 248 (2020) 118489.
[14] W. Zhang, X. Yao, T. Yang, C. Liu, Z. Zhang, Increasing mechanical strength and acid resistance of geopolymers by incorporating different siliceous materials, Construction & Building Materials, 175 (2018) 411-421.
[15] A. Özcan, M.B. Karakoç, Evaluation of sulfate and salt resistance of ferrochrome slag and blast furnace slag‐based geopolymer concretes, Structural Concrete, 20(5) (2019) 1607-1621.
[16] S. Luhar, S. Chaudhary, I. Luhar, Thermal resistance of fly ash based rubberized geopolymer concrete, Journal of Building Engineering, 19 (2018) 420-428.
[17] R. Zhao, Y. Yuan, Z. Cheng, T. Wen, J. Li, F. Li, Z.J. Ma, Freeze-thaw resistance of Class F fly ash-based geopolymer concrete, Construction & Building Materials, 222 (2019) 474-483.
[18] F.N. Değirmenci, Freeze-Thaw and fire resistance of geopolymer mortar based on natural and waste pozzolans,  (2018).
[19] M.J. Nadoushan, A.A. Ramezanianpour, The effect of type and concentration of activators on flowability and compressive strength of natural pozzolan and slag-based geopolymers, Construction & Building Materials, 111 (2016) 337-347.
[20] A.A. Ramezanianpour, M.A. Moeini, Mechanical and durability properties of alkali activated slag coating mortars containing nanosilica and silica fume, Construction & Building Materials, 163 (2018) 611-621.
[21] P. Duxson, J.L. Provis, G.C. Lukey, S.W. Mallicoat, W.M. Kriven, J.S. Van Deventer, Understanding the relationship between geopolymer composition, microstructure and mechanical properties, Colloids & Surfaces A: Physicochemical & Engineering Aspects, 269(1-3) (2005) 47-58.
[22] ASTM C989 / C989M-18a, Standard Specification for Slag Cement for Use in Concrete and Mortars, ASTM International, West Conshohocken, PA, 2018.
[23] ASTM C778-17, Standard Specification for Standard Sand, ASTM International, West Conshohocken, PA, 2017.
[24] P. Dashti, Mechanical and durability properties of silica fume blended cement concrete against chloride ions attack and carbonation, MSc Thesis, Amirkabir University of Technology (Tehran Polytechnic), 2019.
[25] A.A. Ramezanianpour, S. Sedighi, M. Kazemian, A. M. Ramezanianpour, Effect of micro silica and slag on the durability properties of mortars against accelerated carbonation and chloride ions attack, 4(4) (2020) 2-2.
[26] S.M.M. Karein, A. Ramezanianpour, T. Ebadi, S. Isapour, M. Karakouzian, A new approach for application of silica fume in concrete: Wet granulation, Construction & Building Materials, 157 (2017) 573-581.
[27] M.J. Nadoushan, Production of geopolymer coatings to improve mechanical properties and durability of concrete against chloride ions penetration, PhD Thesis, Amirkabir University of Technology (Tehran Polytechnic), 2017, (in Persian).
[28] ASTM C230, Standard Specification for Flow Table for Use in Tests of Hydraulic Cement, ASTM International, West Conshohocken, PA.
[29] ASTM C109 / C109M-20a, Standard Test Method for Compressive Strength of Hydraulic Cement Mortars, ASTM International, West Conshohocken, PA, 2020.
[30] ASTM D7234-19, Standard Test Method for Pull-Off Adhesion Strength of Coatings on Concrete Using Portable Pull-Off Adhesion Testers, ASTM International, West Conshohocken, PA, 2019.
[31] ASTM C596-18, Standard Test Method for Drying Shrinkage of Mortar Containing Hydraulic Cement, ASTM International, West Conshohocken, PA, 2018.
[32] EN 480-5, Admixtures for concrete, mortar and grout. Test methods. Determination of capillary absorption, European Standard (EN), (1997).
[33] BS EN 12390-8, Testing hardened concrete. Depth of penetration of water under pressure.
[34] NT Build 492, Nord Test Method: Chloride Migration Coefficients from Non Steady-State, 1999.
[35] R. Banar, P. Dashti, A. Zolfagharnasab, A.M. Ramezanianpour, A.A. Ramezanianpour, A comprehensive comparison between using silica fume in the forms of water slurry or blended cement in mortar/concrete, Journal of Building Engineering, 46 (2022) 103802.
[36] F. Moodi, S. Norouzi, P. Dashti, Mechanical properties and durability of alkali-activated slag repair mortars containing silica fume against freeze-thaw cycles and salt scaling attack, Advances in concrete construction, (2021).
[37] E.R. Dehkordi, A.A. Ramezanianpour, F. Moodi, Application of pre-fabricated geopolymer permanent formworks (PGPFs): A novel approach to provide durability and mechanical strength of reinforced concrete, Journal of Building Engineering, 45 (2022) 103517.
[38] F. Moodi , A.A. Ramezanianpor, F. Farhadian, P. Dashti, Durability of cementitious and geopolymer coating mortars against sulfuric acid attack, Amirkabir Journal of Civil Engineering, 53(9) (2021) 6-6.
[39] A.A. Ramezanianpour, F.B. Zadeh, A. Zolfagharnasab, A.M. Ramezanianpour, Mechanical properties and chloride ion penetration of alkali activated slag concrete, in:  High Tech Concrete: Where Technology and Engineering Meet, Springer, 2018, pp. 2203-2212.
[40] F.B. Zadeh, Mechanical properties and chloride ions penetration in alkali acticvated slag concrete, MSc Thesis, Amirkabir University of Technology (Tehran Polytechnic), 2015.