Farklı Konsantrasyonlarda Sodyum Sülfata Maruz Kalan Silis Dumanı İçerikli Betonların Sülfat Direncinin İncelenmesi

Yıl 2023, Cilt: 13 Sayı: 4, 2706 - 2716, 01.12.2023

Emrah Aksakal , Zinnur Çelik , Ahmet Ferhat Bingöl

https://doi.org/10.21597/jist.1323279

Öz

Bu çalışmada, farklı ikame seviyelerinde silis dumanı (SD) içeren betonların sodyum sülfat çözeltisine maruz kaldıktan sonraki özellikleri incelenmiştir. Bu amaçla, çimento ağırlığına göre %5, %10 ve %15 oranında SD kullanılmıştır. Karışımlar %3, %5 ve %10 konsantrasyona sahip Na2SO4 çözeltisinde 30, 60, 90 ve 120 günlük periyodlarda bekletilmiştir. Tüm karışımların çözeltiye maruz kalma sonrası basınç dayanım kayıpları ve genleşme oranları tespit edilmiştir. Ayrıca karışımların taze beton özelliği olarak çökme değerleri ölçülmüştür. Özellikle SD ilaveli karışımların çökme değerlerinin azalmaması için süper akışkanlaştırıcı kullanılmıştır. Böylelikle SD ilaveli karışımların çökme değerlerinde kayda değer düşüşler meydana gelmemiştir. Test sonuçları, SD varlığının, sodyum sülfat etkisinden kaynaklanan dayanım kaybı üzerinde olumlu bir etkiye sahip olduğunu göstermiştir. Sodyum sülfat saldırısına karşı en iyi direnç, %15'lik SD ikamesi ile elde edilmiş olup; 120 günlük periyodda ve tüm konsantrasyon oranlarında %3 ile %8 arasında dayanım kaybı tespit edilmiştir. Özellikle %3 konsantrasyonlu çözeltiye maruz bırakılan numunelerin erken yaşlarda (30 ve 60.gün) dayanımlarında artış meydana gelmiştir. Bu durum, gözenek boşluklarının genişleyen ürünler tarafından doldurulmasına ve harç matrisinin yoğunlaştırılmasına bağlanabilir. %10 konsantrasyona sahip çözeltide bekletilen kontrol numunesinin bağıl artık basınç dayanımı %94 ile %77.95 aralığında değişirken, SD-15 numunesi için bu değerler %100.31 ile %92.35 aralığında elde edilmiştir. Ayrıca Na2SO4 çözeltisine maruz kalan numunelerin genleşme oranları, basınç dayanımı sonuçları ile benzerlik gösterdiği gözlemlenmiştir.

Anahtar Kelimeler

Na2SO4, Sülfat direnci, Silis dumanı, Konsantrasyon, Genleşme oranı

Investigation of Sulphate Resistance of Concretes Containing Silica Fume Exposed to Sodium Sulphate at Different Concentrations

Öz

In this study, the properties of concretes containing silica fume (SF) at different substitution levels after exposure to sodium sulfate solution were investigated. For this purpose, 5%, 10% and 15% SF were used according to the cement weight. The mixtures were kept in Na2SO4 solution with 3%, 5% and 10% concentrations for 30, 60, 90 and 120 day periods. Compressive strength losses and expansion ratios of all mixtures after exposure to solution were determined. In addition, the slump values of the mixtures as fresh concrete properties were also measured. A superplasticizer was used especially in order not to decrease the slump values of SF added mixtures. Thus, there was no significant decrease in the slump values of the SF-added mixtures. The test results showed that the presence of SF had a positive effect on the strength loss caused by the sodium sulfate effect. The best resistance to sodium sulfate attack was obtained with 15% SF substitution; A strength loss of 3% to 8% was detected in a 120-day period and at all concentrations. In particular, the strength of the samples exposed to 3% concentrated solution increased at early ages (30 and 60 days). This can be attributed to the filling of the pore spaces by the expanding products and the thickening of the mortar matrix. While the relative residual compressive strength of the control sample kept in 10% concentration solution ranged between 94% and 77.95%, these values were obtained between 100.31% and 92.35% for the SD-15 sample. In addition, it was observed that the expansion values of the samples exposed to the Na2SO4 solution were similar to the compressive strength results.

Anahtar Kelimeler

Na2SO4, Sulfate resistance, Silica füme, Concentration, Expansion value

Kaynakça

• Al-Amoudi, O. S. B. (1998). Sulfate attack and reinforcement corrosion in plain and blended cements exposed to sulfate environments. Building and Environment, 33(1), 53-61.
• Al-Dulaijan, S. U., Maslehuddin, M., Al-Zahrani, M. M., Sharif, A. M., Shameem, M., & Ibrahim, M. (2003). Sulfate resistance of plain and blended cements exposed to varying concentrations of sodium sulfate. Cement and Concrete Composites, 25(4-5), 429-437.
• ASTM C 1012-02.(2002). Standard test method for length change of hydraulic-cement mortars exposed to a sulfate solution. United States of America: ASTM International, 1-6.
• Bakharev, T. (2005). Durability of geopolymer materials in sodium and magnesium sulfate solutions. Cement and concrete research, 35(6), 1233-1246.
• Brown, P. W., & Badger, S. (2000). The distributions of bound sulfates and chlorides in concrete subjected to mixed NaCl, MgSO4, Na2SO4 attack. Cement and Concrete Research, 30(10), 1535-1542.
• Çelik, Z., Bingöl, A. F., & Ağsu, A. S. (2022). Fresh, mechanical, sorptivity and rapid chloride permeability properties of self-compacting concrete with silica fume and fly ash. Iranian Journal of Science and Technology, Transactions of Civil Engineering, 1-11.
• El-Hachem, R., Rozière, E., Grondin, F., & Loukili, A. (2012). New procedure to investigate external sulphate attack on cementitious materials. Cement and Concrete Composites, 34(3), 357-364.
• Figg, J. (1999). Field studies of sulfate attack on concrete. Materials Science of Concrete: Sulfate Attack Mechanisms, Ed. J. Marchand and JP Skalny. American Ceramic Society, Westerbrook, Ohio, 315-323.
• Hekal, E. E., Kishar, E., & Mostafa, H. (2002). Magnesium sulfate attack on hardened blended cement pastes under different circumstances. Cement and Concrete Research, 32(9), 1421-1427.
• Ikumi, T., & Segura, I. (2019). Numerical assessment of external sulfate attack in concrete structures. A review. Cement and Concrete Research, 121, 91-105.
• Lee, S. T., Moon, H. Y., & Swamy, R. N. (2005). Sulfate attack and role of silica fume in resisting strength loss. Cement and Concrete Composites, 27(1), 65-76.
• Liu, T., Zou, D., Teng, J., & Yan, G. (2012). The influence of sulfate attack on the dynamic properties of concrete column. Construction and Building Materials, 28(1), 201-207.
• Lv, X., Yang, L., Li, J., & Wang, F. (2022). Roles of fly ash, granulated blast-furnace slag, and silica fume in long-term resistance to external sulfate attacks at atmospheric temperature. Cement and Concrete Composites, 133, 104696.
• Mardani-Aghabaglou, A., Sezer, G. İ., & Ramyar, K. (2014). Comparison of fly ash, silica fume and metakaolin from mechanical properties and durability performance of mortar mixtures view point. Construction and Building Materials, 70, 17-25.
• Mazloom, M., Ramezanianpour, A. A., & Brooks, J. J. (2004). Effect of silica fume on mechanical properties of high-strength concrete. Cement and concrete composites, 26(4), 347-357.
• Park, C. K., Noh, M. H., & Park, T. H. (2005). Rheological properties of cementitious materials containing mineral admixtures. Cement and concrete research, 35(5), 842-849.
• Planel, D., Sercombe, J., Le Bescop, P., Adenot, F., & Torrenti, J. M. (2006). Long-term performance of cement paste during combined calcium leaching–sulfate attack: kinetics and size effect. Cement and Concrete Research, 36(1), 137-143.
• Santhanam, M., Cohen, M. D., & Olek, J. (2003). Effects of gypsum formation on the performance of cement mortars during external sulfate attack. Cement and concrete research, 33(3), 325-332.
• Sezer, G. İ. (2012). Compressive strength and sulfate resistance of limestone and/or silica fume mortars. Construction and Building Materials, 26(1), 613-618.
• Skalny, J., & Pierce, J. (1999). Sulfate attack issues. Material Science of Concrete—Sulfate Attack Mechanisms, American Ceramic Society, Westerville, OH, 49-64.
• Şahmaran, M., Kasap, O., Duru, K., & Yaman, I. O. (2007). Effects of mix composition and water–cement ratio on the sulfate resistance of blended cements. Cement and Concrete composites, 29(3), 159-167.
• TS EN 12350-2, (2019). Beton - Taze beton deneyleri - Bölüm 2: Çökme (slump) deneyi. Türk Standardları Enstitüsü. Ankara.
• TS EN 12390-3, (2019). Beton – sertleşmiş beton deneyleri- Bölüm 3: Deney numunelerinde basınç dayanımının tayini, Türk Standartları Enstitüsü, Ankara.
• Wang, H., Chen, Z., Li, H., & Sun, X. (2021). Numerical simulation of external sulphate attack in concrete considering coupled chemo-diffusion-mechanical effect. Construction and Building Materials, 292, 123325.
• Wang, D., Zhou, X., Meng, Y., & Chen, Z. (2017). Durability of concrete containing fly ash and silica fume against combined freezing-thawing and sulfate attack. Construction and Building Materials, 147, 398-406.
• Yazıcı, H., Yardımcı, M. Y., Aydın, S., & Karabulut, A. Ş. (2009). Mechanical properties of reactive powder concrete containing mineral admixtures under different curing regimes. Construction and building materials, 23(3), 1223-1231.