Uçucu Kül Tabanlı Jeopolimerlerin Çiçeklenme Kontrol Yöntemlerinin Geliştirilmesi

Çimento üretiminden kaynaklanan karbon emisyonlarının çevresel etkileri tartışılmaya başlandığından beri, çimentoya alternatif bir malzeme aranmaktadır. Jeopolimerler, binada çimento yerine kullanılmaya uygun yeni nesil malzemelerdir. Jeopolimer teknolojisi kapsamında, uçucu kül ve yüksek fırın cürufu gibi atık malzemelerin yeniden kullanılması, hem atık stokunun azaltılmasını hem de bilim dünyasını heyecanlandıran yeni nesil malzemenin üretimini sağlamaktadır. Fakat çeşitli sorunlar bu teknolojinin ilerlemesini engellemektedir. Çiçeklenme jeopolimer teknolojisinin geliştirilmesinin önünde önemli bir problemdir. Jeopolimerlerin ıslanması sonucu yüzeyleri üzerinde oluşan beyaz kalıntılara çiçeklenme denir. İlk aşamada yalnızca görsel bir sorun gibi görünse de, sonraki aşamalarda yapısal sorunlara neden olabilir. Bu nedenle, ele alınması gereken bir konudur. Bu çalışmada, bu sorunu önlemek veya en aza indirmek için çalışmalar yapılmıştır. Farklı molaritelerde hazırlanan ve farklı sıcaklıklarda kürlenen jeopolimer köpük numunelerin çiçeklenme davranışı incelenmiştir. Yüksek molaritelerde hazırlanan numunelerin ve daha düşük sıcaklıklarda kürlenen numunelerin çiçeklenme problemine daha yatkın olduğu tespit edilmiştir.

Development of Efflorescence Control Methods of Fly Ash Based Foam Geopolymers

Since the environmental impacts of carbon emissions due to the cement production have started to bediscussed, an alternative material has been sought. Geopolymers are new generation materials thatare good candidates to be used instead of cement in the structures. Within the scope of geopolymertechnology, the reuse of industrial by-products such as fly ash and blast furnace slag enable reuse ofboth the reduction of waste stock and the production of new generation material which excites thescientific world. However, various problems that have been focused on preventing the advancement ofthis technology. Efflorescence is a critical problem for the development of geopolymer technology.White residues formed on the surfaces of the materials produced from geopolymer wetting are referredto as efflorescence. Although it may seem like a visual problem in the initial stage, it may causestructural problems in later stages. Therefore, it is an issue that needs to be addressed. In this study,studies were made to prevent or minimize this problem. Efflorescence behavior of geopolymer foamsamples prepared in different molarities and cured at different temperatures were investigated. It wasdetermined that the samples prepared at high molarities and the samples cured at lower temperaturesare more prone to the problem of efflorescence.

PDF

___

Allahverdi, A., Najafi K., Hossain, K.M.A. and Lachemi, M., 2014. Methods to Control Efflorescence in Alkali-Activated Cement- Based Materials. Handbook of Alkali- Activated Cements, Mortars and Concretes. Woodhead Publishing Limited, 463-483.
Bai, C., Colombo, P. 2018. Processing , Properties and Applications of Highly Porous Geopolymers : A review. Ceramics International, 44(14), 16103–16118.
Damtoft, J.S., Lukasik, J., Herfort, D., Sorrentino, D. and Gartner, E.M., 2008. Sustainable Development and Climate Change Initiatives. Cement and Concrete Research 38 (2): 115–27.
Davidovits, J., 1994. Global Warming Impact on the Cement and Aggregates Industries. World Resource Review 6 (2): 263–78.
Davidovits, J., 2008. Geopolymer Chemistry and Applications. Saint-Quentin: Institut Géopolymère, 102-18.
Davidovits, J., 2015. False Values on CO2 Emission For Geopolymer Cement/Concrete. Scientific Papers, Technical Paper 24.
Deventer, J., Van, S.J., Provis, J.L. and Duxson, P., 2012. Technical and Commercial Progress in the Adoption of Geopolymer Cement. Minerals Engineering 29:89–1
Dow, C., Glasser, F.P., 2003. Calcium Carbonate Efflorescence on Portland Cement and Building Materials. Cement and Concrete Research 33 (1): 147–54..
Duxson, P., Fernández-Jiménez, A., Provis, J.L., Lukey, G.C., Palomo, A., Van Deventer, J.S.J. 2007. Geopolymer Technology: The Current State of the Art. Journal of Materials Science 42 (9): 2917–33.
Gatti, S. and Prasad, D.S.V., 2017. A Comparative Study on Compressive Strength of Geo Polymer Concrete Using Partial Replacement of Cement With Ggbs. International Journal of Recent Trends in Engineering and Research 3 (8): 267–81.
Hajimohammadi, A., Ngo, T., Mendis, P., Sanjayan, J., 2017. Regulating the chemical foaming reaction to control the porosity of geopolymer foams. Materials and Design, 120, 255–265.
Kaur, M., Singh, J., Kaur, M., 2018. Microstructure and Strength Development of Fly Ash-Based Geopolymer Mortar: Role of Nano- Metakaolin. Construction and Building Materials 190: 672–79.
Lecomte, I., Henrist, C., Liégeois, M., Maseri, F., Rulmont, A., Cloots, R., 2006. (Micro)- Structural Comparison between Geopolymers, Alkali-Activated Slag Cement and Portland Cement. Journal of the European Ceramic Society 26 (16): 3789–97.
Liew, Y.M., Nizar, I.K., Kamarudin, H., Heah, C.Y., Bnhussain, M., Mustafa Al Bakri, A. M., Ruzaidi, C. M., Luqman, M., 2013. Kaolin- Based Geopolymers with Various NaOH Concentrations. International Journal of Minerals, Metallurgy, and Materials 20 (3): 313–22.
McLellan, B.C., Williams, R.P., Lay, J., Riessen, A V., Corder, G.D., 2011. Costs and Carbon Emissions for Geopolymer Pastes in Comparison to Ordinary Portland Cement. Journal of Cleaner Production 19 (9–10): 1080–90.
Medri, V., Papa, E., Dedecek, J., Jirglova, H., Benito, P., Vaccari, A., Landi, E. 2013. Effect of metallic Si addition on polymerization degree of in situ foamed alkali-aluminosilicates. Ceramics International, 39(7), 7657–7668.
Neupane, K., Chalmers, D., Kidd, P., 2018. High- Strength Geopolymer Concrete- Properties , Advances in Materials 7 (2): 15–25.
Novais, R. M., Buruberri, L. H., Ascensão, G., Seabra, M. P., Labrincha, J. A. 2016. Porous biomass fly ash-based geopolymers with tailored thermal conductivity. Journal of Cleaner Production, 119: 99–107.
Novais, R.M., Pullar, R.C., Labrincha, J.A. 2019. Geopolymer foams: an overview of recent advancements. Progress in Materials Science, 100621.
Ohji, T., Fukushima, M. 2012. Macro-porous ceramics: processing and properties. International Materials Reviews, 57(2), 115–131.
Škvara, F., Svoboda, P., Dolezal, J., 2008. Geopolymer Concrete-an Ancient Material Too? Ceramics − Silik{á}ty 52 (4): 296–98.
Srinivasan, K., Sivakumar, A., 2013. Geopolymer Binders: A Need for Future Concrete Construction. ISRN Polymer Science 1–8.
Strozi Cilla, M., Colombo, P., Raymundo Morelli, M. (2014). Geopolymer foams by gelcasting. Ceramics International, 40(4), 5723–5730.
Subaer, S., 2004. Influence of Aggregate on the Microstructure of Geopolymer, PhD Thesis, Curtin University, pp 226.
Szklorzová, H., Bílek, V., 2008. Influence of Alkali Ions in the Activator on the Performance of Alkali Activated Mortars. Proceedings of the 3rd International Symposium on Non- Traditional Cement and Concrete, 777–84.
Thaarrini, J., Dhivya, S., 2016. Comparative Study on the Production Cost of Geopolymer and Conventional Concretes. International Journal of Civil Engineering Research 7 (2): 2278–3652.
Thakur, V.K., Thakur, M. K., Kessler, M.R., 2017. Handbook of Composites from Renewable Materials. Physico-Chemical and Mechanical Characterization, 3:563-580.
Vaou, V., Panias, D. 2010. Thermal insulating foamy geopolymers from perlite. Minerals Engineering, 23(14), 1146–1151.
Zhang, Z., Provis, J.L., Reid, A., Wang, H. 2014. Geopolymer foam concrete: An emerging material for sustainable construction. Construction and Building Materials, 56: 113–127.
Zhang, Z., Provis, J. L., Ma, X., Reid, A., Wang, H., 2018. Efflorescence and Subflorescence Induced Microstructural and Mechanical Evolution in Fly Ash-Based Geopolymers. Cement and Concrete Composites 92: 165–77.