TY - JOUR T1 - The Compressive Strength Development of Alkali Activated Fly Ash/Slag Concretes with Different Alkali Activator Ratios AU - Niş, Anıl PY - 2019 DA - June Y2 - 2019 JF - International Journal of Engineering Technologies IJET JO - IJET PB - İstanbul Gelisim University WT - DergiPark SN - 2149-0104 SP - 84 EP - 89 VL - 5 IS - 2 LA - en AB - Recently, geopolymer oralkali-activated concrete takes great attention due to low carbon footprintsince fly ash and ground granulated blast furnace slag (industrial by-productmaterials) has been utilized as binder materials in the alkali-activatedconcrete. In this research, the compressive strength (CS) development of thealkali-activated fly ash/slag (AAFAS) concrete was investigated in an ambientenvironment at 7., 14., 28., and 56. days using alkali activator (sodiumsilicate to sodium hydroxide) ratios of 1, 1.5, 2, and 2.5 with 6M SH (low)concentration. In addition, the effect of delayed oven-curing condition wasalso studied at 56.day. The results indicated that for theambient-cured specimens with 6M SH concentration, the maximum and minimum CSwere reached in the AAFSS concrete with alkali activator (SS/SH) ratios of 2and 1, respectively. The AAFAS concrete with an alkali activator ratio of 2.5showed the lowest CS enhancement after 7.day and 14.day, while the AAFASspecimens with an alkali activator ratio of 1.5 performed the least CSimprovement at 28.day in the ambient environment. Meanwhile, the highest CSenhancement was observed in the specimens with an alkali activator ratio of 2for all ages. Due to the delayed oven-curing, theleast and the highest CS enhancements were observed in the AAFAS specimens withalkali activator ratios of 2 and 1.5, respectively. The results pointed outthat AAFAS concrete with a higher alkali activator ratio (≥2) should be usedfor structural applications in the ambient environment. KW - Alkali activated fly ash/slag concrete KW - alkali activator KW - delayed oven-curing KW - sodium silicate to sodium hydroxide ratio CR - S. A. Hasanein, H. M. Khate, S. A. A. El-Enein, and H.A. El-Sayed, “Resistance of alkali activated water-cooled slag geopolymer to sulphate attack”, Ceramics-Silikáty, vol. 55, no. 2, pp. 153–160, 2011. CR - A. Niş, ‘‘Mineral katkılı betonların kimyasal durabilitesinin toplam bağlayıcı miktarı ve eşdeğer su/çimento parametreleriyle beraber incelenmesi’’, Balıkesir Üniversitesi Fen Bilimleri Enstitüsü Dergisi, vol. 21, no. 1, pp. 459-473, 2019. CR - A. E. Kurtoglu, R. Alzeebaree, O. Aljumaili, A. Nis, M. E. Gulsan, G. Humur, and A. Cevik, ‘‘Mechanical and durability properties of fly ash and slag based geopolymer concrete’’, Advances in Concrete Construction, vol. 6, no. 4, pp. 345–362, 2018. CR - A. Çevik, R. Alzeebaree, G. Humur, A. Niş, and M. E. Gülşan, ‘‘Effect of nano-silica on the chemical durability and mechanical performance of fly ash based geopolymer concrete’’, Ceramics International, vol. 44, no. 11, pp. 12253-12264, 2018. CR - R. Alzeebaree, M.E Gulsan, A. Nis, A. Mohammedameen, and A. Cevik, ‘‘Performance of FRP confined and unconfined geopolymer concrete exposed to sulfate attacks’’, Steel and Composite Structures, vol. 29, no. 2, pp. 201-218, 2018. CR - R. Alzeebaree, A. Çevik, B. Nematollahi, J. Sanjayan, A. Mohammedameen, and M.E. Gülşan, ‘‘Mechanical properties and durability of unconfined and confined geopolymer concrete with fiber reinforced polymers exposed to sulfuric acid’’, Construction and Building Materials, vol. 215, pp. 1015-1032, 2019. CR - M. E. Gülşan, R. Alzeebaree, A. A. Rasheed, A. Niş, and A.E. Kurtoğlu, ‘‘Development of fly ash/slag based selfcompacting geopolymer concrete using nano-silica and steel fiber’’, Construction and Building Materials, vol. 211, pp. 271-283, 2019. CR - F. N. Okoye, S. Prakash, and N. B. Singh, ‘‘Durability of fly ash based geopolymer concrete in the presence of silica fume’’, Journal of Cleaner Production, vol. 149, pp. 1062- 1067, 2017. CR - J. Davidovits, Geopolymer Chemistry and Applications, 2nd Edn., Inst. Geopolymer, SaintQuentin, France, 2008. CR - J. Davidovits, ‘‘Geopolymer cement to minimize carbon-dioxde greenhouse-warming’’, Ceram. Trans., vol. 37, pp. 165–182, 1993. CR - S. Saha and C. Rajasekaran, ‘‘Enhancement of the properties of fly ash based geopolymer paste by incorporating ground granulated blast furnace slag’’, Construction and Building Materials, vol. 146, pp. 615-620, 2017. CR - A. Fernández-Jiménez, J. G. Palomo, and F. Puertas, ‘‘Alkali-activated slag mortars: mechanical strength behaviour’’, Cement and Concrete Research, vol. 29, no. 8, pp. 1313-1321, 1999. CR - K. Somna, C. Jaturapitakkul, P. Kajitvichyanukul, and P. Chindaprasirt, ‘‘NaOH-activated ground fly ash geopolymer cured at ambient temperature’’, Fuel, vol. 90, no. 6, pp. 2118-2124, 2011. CR - T. Bakharev, ‘‘Durability of geopolymer materials in sodium and magnesium sulfate solutions’’, Cement and Concrete Research, vol. 35, no.6, 1233-1246, 2005. CR - C. B. Cheah, M. H. Samsudin, M. Ramli, W.K. Part, and L.E. Tan, L. E. ‘‘The use of high calcium wood ash in the preparation of Ground Granulated Blast Furnace Slag and Pulverized Fly Ash geopolymers: A complete microstructural and mechanical characterization’’, Journal of Cleaner Production, vol. 156, pp. 114-123, 2017. CR - N. K. Lee, J. G. Jang, and H.K. Lee, ‘‘Shrinkage characteristics of alkali-activated fly ash/slag paste and mortar at early ages’’, Cement and Concrete Composites, vol. 53, pp. 239-248, 2014. CR - M. Hu, X. Zhu, and F. Long, ‘‘Alkali-activated fly ashbased geopolymers with zeolite or bentonite as additives’’, Cement and Concrete Composites, vol. 31, no. 10, pp. 762-768, 2009. CR - G. Görhan, and G. Kürklü, ‘‘The influence of the NaOH solution on the properties of the fly ash-based geopolymer mortar cured at different temperatures’’, Composites part b: engineering, vol. 58, pp. 371-377, 2014. CR - P. Duxson, , J. L. Provis, G. C. Lukey, S. W. Mallicoat, W. M. Kriven, and J. S. Van Deventer, ‘‘Understanding the relationship between geopolymer composition, microstructure and mechanical properties’’, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 269, no. 1-3, pp. 47-58, 2005. CR - G.B. Singh, and K. V. Subramaniam, ‘‘Evaluation of sodium content and sodium hydroxide molarity on compressive strength of alkali activated low-calcium fly ash’’, Cement and Concrete Composites, vol. 81, pp. 122-132, 2017. CR - M. Albitar, M. M. Ali, P. Visintin, and M. Drechsler, ‘‘Durability evaluation of geopolymer and conventional concretes’’, Construction and Building Materials, vol. 136, pp. 374-385, 2017. CR - M. Soutsos, A. P. Boyle, R. Vinai, A. Hadjierakleous, and S. J. Barnett, ‘‘Factors influencing the compressive strength of fly ash based geopolymers’’, Construction and Building Materials, vol. 110, pp. 355-368, 2016. UR - https://dergipark.org.tr/en/pub/ijet/article/565200 L1 - https://dergipark.org.tr/en/download/article-file/742673 ER -