Effect of Al in slag blended cement paste under sulfate attack

Abstract

Unilateral sulfate attack of cementitious materials containing 40% slag with different water to binder ratios was investigated. The results showed that the degradation of slag blended cement pastes was nearly from the corners of paste surface with cracking and spallings, water-to-binder(w/b) ratio made a significant sense to the damage that low w/b ratio led to little weight loss, less cracking and spalling damage and vice versa. Microstructural experimental results demonstrated that in the three different stages of sulfate attack, degradation of pastes was primarily associated with the migration behavior and bonding configuration of aluminum, in the early ages Al was mostly present in C-(A)-S-H, and thus, the damage of pastes hardly appeared while at later ones Al had been largely transferred from C-(A)-S-H into AFt, leading to expansive damage.

Keywords

sulfate attack / slag / aluminum / ²⁷Al NMR

References

[1] Jin Z Q. Durability and Service Life Prediction of Concrete Exposed to Harsh Environment in West of China[D]. 2006 Nan Jing: Southwest University.

[2] Mittermayr F, Rezvani M, Baldermann A, et al. Sulfate Resistance of Cement-Reduced Eco-Friendly Concretes[J]. Cement and Concrete Composites, 2015, 55: 364-373.

[3] Kunther W, Lothenbach B, Skibsted J. Influence of the Ca/Si Ratio of the C–S–H Phase on the Interaction with Sulfate Ions and Its Impact on the Ettringite Crystallization Pressure[J]. Cement and Concrete Research, 2015, 69(1): 37-49.

[4] Hossack A M, Thomas M D A. Varying Fly Ash and Slag Contents in Portland Limestone Cement Mortars Exposed to External Sulfates[J]. Construction and Building Materials, 2015, 78: 333-341.

[5] Chinchón-Payá S, Aguado A, Nugterenc H W. External Sulfate Attack in Dam Concretes with Thaumasite Formation[J]. Materiales De Construction, 2015, 65(317): 1-9.

[6] Gao R D, Li Q B, Zhao S B, et al. Deterioration Mechanisms of Sulfate Attack on Concrete under Alternate Action[J]. Journal of Wuhan University of Technology-Materials Science Edition, 2010, 25(2): 355-360.

[7] Niu D T, Jiang L, Fei Q N. Deterioration Mechanism of Sulfate Attack on Concrete under Freeze-thaw Cycles[J]. Journal of Wuhan University of Technology-Materials Science Edition, 2013, 28(6): 1172-1177.

[8] Long G C, Xie Y J, Tang X G. Evaluating Deterioration of Concrete by Sulfate Attack[J]. Journal of Wuhan University of Technology-Materials Science Edition, 2007, 22(3): 572-578.

[9] Liang Y N, Yuan Y S. Mechanism of Concrete Destruction under Sodium Sulfate and Magnesium Sulfate Solution[J]. Journal of the Chinese Cement Society, 2007, 35(4): 504-508.

[10] Xing F, Feng N Q. Durability of Concrete and Concrete Structure[M]. 2008 Beijing: China Machine Press.

[11] Li B. Mechanism and Influence Factors of Concrete under Sulfate Attack[J]. Technology and Market, 2009, 16(8): 10-11.

[12] Müllauer W, Beddoe R E, Heinz D. Sulfate Attack Expansion Mechanisms[J]. Cement and Concrete Research, 2013, 52: 208-215.

[13] Ben-Yair M. The Effect of Chlorides on Concrete in Hot and Arid Regions[J]. Cement and Concrete Research, 1974, 3(4): 405-416.

[14] Al-Amoudi O S B, Maslehuddin M, Saadi M M. Effect of Magnesium Sulfate and Sodium Sulfate on the Durability Performance of Plain and Blended Cements[J]. ACI Material Journal, 1995, 1(92): 15-24.

[15] Ye Q, Shen C J, Sun S, et al. The Sulfate Corrosion Resistance Behavior of Slag Cement Mortar[J]. Construction and Building Materials, 2014, 71(4): 202-209.

[16] Komljenović M M, Bascarević Z, Marjanović N, et al. Decalcification Resistance of Alkali-Activated Slag[J]. Journal of Hazardous Materials, 2012, 233–234: 112-121.

[17] Bakharev T, Sanjayan J G, Cheng Y B. Sulfate Attack on Alkali-Activated Slag Concrete[J]. Cement and Concrete Research, 2002, 32(2): 211-216.

[18] Al-Amoudi O S B. Attack on Plain and Blended Cements Exposed to Aggressive Sulfate Environments[J]. Cement and Concrete Composites, 2002, 24(3): 305-316.

[19] Dung N T, Chang T P, Chen C T. Engineering and Sulfate Resistance Properties of Slag-CFBC Fly Ash Paste and Mortar[J]. Construction and Building Materials, 2014, 63(8): 40-48.

[20] Tang S W, Yao Y, Andrade C, et al. Recent Durability Studies on Concrete Structure [J]. Cement and Concrete Research, 2015, 78: 143-154.

[21] Patsikas N, Katsiotis N, Pipilikaki P, et al. Durability of Mortars of White Cement Against Sulfate Attack in Elevated Temperatures[J]. Construction and Building Materials, 2012, 36(4): 1082-1089.

[22] Schmidt T, Lothenbach B, Romer M, et al. Physical and Microstructural Aspects of Sulfate Attack on Ordinary and Limestone Blended Portland Cements[J]. Cement and Concrete Research, 2009, 39(12): 1111-1121.

[23] Mehta P K. Mechanism of Expansion Associated with Ettringite Formation[J]. Cement and Concrete Research, 1973, 3(1): 1-6.

[24] Mesbah A. A New Investigation of the Cl⁻-CO₃ ²⁻ Substitution in AFm Phases[J]. Journal of the American Ceramic Society, 2011, 94(6): 1901-1910.

[25] Brunet F. Characterization by Solid-State NMR and Selective Dissolution Techniques of Anhydrous and Hydrated CEM V Cement Pastes[J]. Cement and Concrete Research, 2010, 40(2): 208-219.

[26] Andersen M D, Jakobsen H J, Skibsted J. Incorporation of Aluminum in the Calcium Silicate Hydrate (C−S−H) of Hydrated Portland Cements: A High-Field ²⁷Al and ²⁹Si MAS NMR Investigation[J]. Inorganic Chemistry, 2003, 42(7): 2280-2287.

[27] Andersen M D, Jakobsen H J, Skibsted J. A New Aluminium-Hydrate Species in Hydrated Portland Cements Characterized by ²⁷Al and ²⁹Si MAS NMR Spectroscopy[J]. Cement and Concrete Research, 2006, 36(1): 3-17.