Investigation of the usage of fly ash containing a high amount of sulfate as a clinker replacement material

Year 2023, Volume: 29 Issue: 5, 507 - 512, 31.10.2023

Murat Saydan Furkan Türk Ülkü Sultan Keskin Hilal Say

Abstract

Tons of fly ash are released every year due to the coal burned in thermal power plants that meet 80% of Türkiye's electrical energy needs. Especially considering the low-quality lignite reserves in Türkiye, the recycling rate of the high sulfate fly ash is relatively low. In concrete production, the use of ash containing high SO3 is not allowed due to the limitation of SO3 ratios of fly ash by regulations. Herein, the usability of fly ash, which has a high sulfate content due to the low-quality lignite reserves in Türkiye, and is therefore wholly waste, as a clinker replacement material was investigated. Fly ash, which has been used as a clinker replacement material, was obtained from Afşin Elbistan thermal power plant. Binders were obtained by grinding together the high sulfate fly ash, clinker and gypsum at different rates. The setting times of the mixtures in the fresh cement paste were determined, and the compressive strengths of the hardened samples were examined. As a result of the study, it was concluded that although the high sulfate fly ash extended the setting time by approximately 29% compared to the reference specimen, it increased the 28-day compressive strength of the hardened specimens up to 14%.

Keywords

Waste, High sulphate fly ash, Clinker, Compressive strength, Cement production

Yüksek oranda sülfat içeren uçucu küllerin klinker ikame malzemesi olarak kullanılabilirliğinin incelenmesi

Abstract

Türkiye’nin elektrik enerjisi ihtiyacının %80’ini karşılayan termik santrallerde yakılan kömürlerden dolayı her yıl tonlarca uçucu kül açığa çıkmaktadır. Özellikle ülkemizdeki düşük kaliteli linyit rezervleri düşünüldüğünde, açığa çıkan yüksek sülfat içeriğine sahip uçucu küllerin geri dönüşüm oranı oldukça düşüktür. İnşaat sektöründe ise yönetmelikler tarafından uçucu küllerin SO3 oranlarının sınırlandırılması sebebiyle yüksek SO3 içeren küllerin kullanımlarına izin verilmemektedir. Bu çalışmada, ülkemizdeki düşük kaliteli linyit rezervleri sebebiyle yüksek sülfat içeriğine sahip olan, dolayısıyla tamamıyla atık durumda bulunan uçucu küllerin, klinker ikame malzemesi olarak kullanılabilirliği araştırılmıştır. Klinker ikame malzemesi olarak kullanılacak olan ve yüksek oranda sülfat içeren uçucu kül Afşin Elbistan termik santralinden temin edilmiştir. Yüksek oranda sülfat içeren uçucu kül, klinker ve alçı ile farklı oranlarda birlikte öğütülerek karışımlar elde edilmiştir. Karışımların taze halde priz süreleri tayin edilmiş, sertleşmiş numunelerin ise basınç dayanımları incelenmiştir. Çalışma sonucunda, yüksek sülfat içeren uçucu külün priz bitiş sürelerini referans numuneye göre yaklaşık %29 uzatmasına rağmen, 28 günlük basınç dayanımlarını %14’e kadar artırdıkları tespit edilmiştir.

Keywords

Atık, Yüksek sülfatli uçucu Küller, Klinker, Basınç dayanımı, Çimento üretimi

References

• [1] United States Geological Survey. “Mineral Commodity Summaries”. https://pubs.usgs.gov/periodicals/mcs2022/mcs2022- cement.pdf (20.01.2022).
• [2] Brooks S, Sharp JH. “Ettringite-Based Cements”. International Symposium Held at Queen Mary and Westfield College, London, United Kingdom, 9-11 July 1990.
• [3] Toniolo N, Boccaccini A.R. “Fly ash-based geopolymers containing added silicate waste. A review”. Ceramics International 43(17), 14545-14551, 2017.
• [4] Joshi RC. “Fly Ash: Production, Variability and Possible Complete Utilization”. Indıan Geotechnıcal Conference, Maharashtra, India, 16-18 December 2010.
• [5] Research and Markets. “Fly Ash Market-Forecasts from 2022 to 2027”. https://www.researchandmarkets.com/reports/557639 8 (20.01.2022).
• [6] European Committee for Standardization. “Fly Ash for Concrete: Definition, Specifications and Conformity Criteria”. Europe, EN 450-1, 2012.
• [7] Barnes I. “Ash utilisation-impact of recent changes in power generation practices”. Clean Coal Centre, International Energy Agency, London, United Kingdom, 10-17, 2010.
• [8] Heidrich C, Feuerborn HJ, Weir A. “Coal combustion products: a global perspective”. World of Coal Ash Conference, Kentucky, United States of America, 22-25 April 2013.
• [9] World Energy Council. “Survey: World Energy Resources: Coal”. London, England, 4184478, 2013.
• [10] International Energy Agency. “Coal Information Overview”. https://www.iea.org/reports/coalinformation-overview (20.01.2022).
• [11] Kaladharan G, Rajabipour F. “Evaluation and beneficiation of high sulfur and high alkali fly ashes for use as supplementary cementitious materials in concrete”. Construction and Building Materials, 339, 127642-127672, 2022.
• [12] Zunino F, Bentz DP, Castro J. “Reducing setting time of blended cement paste containing high-SO3 fly ash (HSFA) using chemical/physical accelerators and by fly ash prewashing”. Cement and Concrete Composites, 90, 14-26, 2018.
• [13] Antiohos SK, Papageorgiou D, Chaniotakis E, Tsimas S. “Mechanical and durability characteristics of gypsum-free blended cements incorporating sulphate-rich reject fly ash”. Cement and Concrete Composites, 29, 550-558, 2007.
• [14] International Energy Agency. “Coal Market Update July 2022”. https://www.iea.org/reports/coal-marketupdate-july-2022 (25.01.2022)
• [15] Türkiye Elektrik İletim Anonim Şirketi. “Türkiye Elektrik Enerjisi 5 Yıllık Üretim Kapasite Projeksiyonu (2018- 2022)”. Ankara, Türkiye, 2018.
• [16] Bayat O. “Characterisation of Turkish fly ashes”. Fuel, 77(9-10), 1059-1066, 1998.
• [17] Choi, SJ, Lee SS, Monteiro PJ. “Effect of Fly Ash Fineness on Temperature Rise, Setting, and Strength Development of Mortar”. Journal of Materials in Civil Engineering, 24(5), 499-505, 2012.
• [18] Chindaprasirt P, Homwuttiwong S, Sirivivatnanon V. “Influence of fly ash fineness on strength, drying shrinkage and sulfate resistance of blended cement mortar”. Cement and Concrete Research, 34(7), 1087-1092, 2004.
• [19] Kiattikomol K, Jaturapitakkul C, Songpiriyakij S, Chutubtim S. “A study of ground coarse fly ashes with different finenesses from various sources as pozzolanic materials”. Cement and Concrete Composites, 23(4-5), 335-343, 2001.
• [20] Türk Mühendis ve Mimar Odaları Birliği İnşaat Mühendisleri Odası. “Afşin Elbistan Termik Santrali”. Türkiye Mühendislik Haberleri. Ankara, Türkiye, 442-443, 2006.
• [21] Gesoglu M, Güneyisi E, Nahhab AH, Yazici H. “The effect of aggregates with high gypsum content on the performance of ultra-high strength concretes and Portland cement mortars”. Construction and Building Materials, 110, 346-354, 2016.
• [22] Wansom S, Chintasongkro P, Srijampan W. “Water resistant blended cements containing flue-gas desulfurization gypsum, Portland cement and fly ash for structural applications”. Cement and Concrete Composites, 103, 134-148, 2019.
• [23] Zeng Q, Li T, Fen-Chong T, Dangla P. “Determination of cement hydration and pozzolanic reaction extents for flyash cement pastes”. Construction and Building Materials, 27, 560-569, 2012.
• [24] Lorenzo MP, Goñi S, Guerrero A. “Activation of Pozzolanic Reaction of Hydrated Portland Cement Fly Ash Pastes in Sulfate Solution”. Journal of the American Ceramic Society, 85, 3071-3075, 2002.
• [25] Saydan M. “Kalsiyum Aluminat Çimentosu Tabanlı Hızlı Dayanım Kazanan Üçlü Sistemlerin Mekanik ve Mikroyapısal Özelliklerinin İncelenmesi”. PhD Thesis, Konya Technical University, Konya, Türkiye, 2021.
• [26] He J, Long G, Ma K, Xie Y. “Influence of fly ash or slag on nucleation and growth of early hydration of cement”. Thermochimia Acta, 701, 178964-178973, 2021.
• [27] Szostak B, Golewski GL. “Effect of Nano Admixture of CSH on Selected Strength Parameters of Concrete Including Fly Ash”. 7th International Conference on Advanced Materials and Structures, Romania, 28-31 March, 2018.
• [28] Zhou F, Pan G, Mi R, Zhan M. “Improving the properties of concrete using in situ-grown C-S-H”. Construction and Building Materials, 276, 122214-122224, 2021.