Effect of Admixtures on Durability Characteristics of Fly Ash Alkali-activated Material

Lukáš Procházka, Jana Boháčová


This paper deals with the possibility of partial replacement of blast furnace slag with fly ash and fly ash after denitrification by SNCR method in alkali-activated materials based on granulated blast furnace slag. The aim of this paper is to verify the effect of fly ash on properties of alkali-activated materials based on blast furnace granulated slag. Frost resistance and resistance to aggressive environments, represented by demineralized water were tested. The reference mixture was based on blast furnace granulated slag activated by sodium water glass with silicate modulus of 2. Mixtures with an ash content of 10, 20, and 30% were then compared with the reference mixture. The influence of the denitrification process on fly ash and its use in mixed alkali activated materials was also compared. As a part of the experiment, alkali-activated pastes were also prepared. Infrared spectroscopy with Furier transformation was subsequently determined on these pastes. The reference mixture achieved the highest compressive strength in the experiment and the strength decreased with increasing amount of fly ash. In terms of flexural strength, the highest values were reached for mixtures with 10% slag replacement by fly ash. In the case of frost resistance, the significant increase of flexural strength, which was 50% for the reference mixture, is particularly interesting. For compressive strength, the frost resistance coefficient ranged from 0.95 to 1.00. In the case of resistance to aggressive environments, no differences were observed in the compressive strength, on the other hand, flexural strength decrease of up to 20% was detected for 10 and 20 percent replacement of slag with fly ash that did not undergo denitrification. Monitored properties did not show any negative effect of the denitrification process on fly ash properties. Infrared spectroscopy identified the main hydration product in the region of 945 cm-1which is a C-(A)-S-H gel and in combined mixtures with fly ash also N-A-S-H gel.


Doi: 10.28991/esj-2020-01247

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Fly Ash; Denitrification; Blast Furnace Slag; Alkali-activated Material; Frost Resistance.


Abdollahnejad, Z., M. Mastali, B. Woof, and M. Illikainen. “High Strength Fiber Reinforced One-Part Alkali Activated Slag/fly Ash Binders with Ceramic Aggregates: Microscopic Analysis, Mechanical Properties, Drying Shrinkage, and Freeze-Thaw Resistance.” Construction and Building Materials 241 (April 2020): 118129. doi:10.1016/j.conbuildmat.2020.118129.

Ismail, Idawati, Susan A. Bernal, John L. Provis, Rackel San Nicolas, Sinin Hamdan, and Jannie S.J. van Deventer. “Modification of Phase Evolution in Alkali-Activated Blast Furnace Slag by the Incorporation of Fly Ash.” Cement and Concrete Composites 45 (January 2014): 125–135. doi:10.1016/j.cemconcomp.2013.09.006.

Gao, X., Q.L. Yu, and H.J.H. Brouwers. “Properties of Alkali Activated Slag–fly Ash Blends with Limestone Addition.” Cement and Concrete Composites 59 (May 2015): 119–128. doi:10.1016/j.cemconcomp.2015.01.007.

Oh, Jae Eun, Paulo J.M. Monteiro, Ssang Sun Jun, Sejin Choi, and Simon M. Clark. “The Evolution of Strength and Crystalline Phases for Alkali-Activated Ground Blast Furnace Slag and Fly Ash-Based Geopolymers.” Cement and Concrete Research 40, no. 2 (February 2010): 189–196. doi:10.1016/j.cemconres.2009.10.010.

Marjanović, N., M. Komljenović, Z. Baščarević, V. Nikolić, and R. Petrović. “Physical–mechanical and Microstructural Properties of Alkali-Activated Fly Ash–blast Furnace Slag Blends.” Ceramics International 41, no. 1 (January 2015): 1421–1435. doi:10.1016/j.ceramint.2014.09.075.

Alcamand, Himad A., Paulo H.R. Borges, Flávio A. Silva, and Ana Carolina C. Trindade. “The Effect of Matrix Composition and Calcium Content on the Sulfate Durability of Metakaolin and Metakaolin/slag Alkali-Activated Mortars.” Ceramics International 44, no. 5 (April 2018): 5037–5044. doi:10.1016/j.ceramint.2017.12.102.

Wong, John Kok Hee, Sien Ti Kok, and Soon Yee Wong. “Fibers, Geopolymers, Nano and Alkali-Activated Materials for Deep Soil Mix Binders.” Civil Engineering Journal 6, no. 4 (April 1, 2020): 830–847. doi:10.28991/cej-2020-03091511.

Humad, Abeer M., Ankit Kothari, John L. Provis, and Andrzej Cwirzen. “The Effect of Blast Furnace Slag/Fly Ash Ratio on Setting, Strength, and Shrinkage of Alkali-Activated Pastes and Concretes.” Frontiers in Materials 6 (February 14, 2019). doi:10.3389/fmats.2019.00009.

Ye, Hailong. “Nanoscale Attraction Between Calcium-Aluminosilicate-Hydrate and Mg-Al Layered Double Hydroxides in Alkali-Activated Slag.” Materials Characterization 140 (June 2018): 95–102. doi:10.1016/j.matchar.2018.03.049.

Ye, Hailong, Chuanqing Fu, and Guojun Yang. “Influence of Dolomite on the Properties and Microstructure of Alkali-Activated Slag with and Without Pulverized Fly Ash.” Cement and Concrete Composites 103 (October 2019): 224–232. doi:10.1016/j.cemconcomp.2019.05.011.

J. Vlček. "Material utilization of slags from iron and steel metallurgy by the alkaline activation method." Habilitation thesis, FMMI VŠB-TUO (2008)

"Kotouč production plant", Available online: www.kotouc.cz (accessed on June 2020).

"OQEMA", Available online: http://www.eurosarm.cz (accessed on June 2020).

ČSN EN 196-1. Methods of testing cement – Part 1: Determination of strength.

ČSN EN 1008 Mixing water for concrete - Specification for sampling, testing and assessing the suitability of water, including water recovered from processes in the concrete industry, as mixing water for concrete.

ČSN EN 196-3 Methods of testing cement – Part 3: Determination of setting times and soundness.

ČSN 722452. Frost resistance test of mortar. Czech Standards Institute.

L. Krajčová Study of pozzolanite and amorphous fraction of metakaolin depending on firing temperature, VŠB – TUO (2017).

J. Boháčová Study of influence of different types of fillers on properties of geopolymer systems based on alkali activated slags, VŠB – TUO (2008).

J. Koňařík Influence of activator on basic properties of alkali activated systems, VŠB – TUO (2014).

Mec, Pavel, Jana Boháčová, and Stanislav Staněk. “Mechanical Properties of Alkali-Activated Material with Waste Aggregate According to Porosity.” Materials Science Forum 865 (August 2016): 53–56. doi:10.4028/www.scientific.net/msf.865.53.

Abdollahnejad, Z., M. Mastali, B. Woof, and M. Illikainen. “High Strength Fiber Reinforced One-Part Alkali Activated Slag/fly Ash Binders with Ceramic Aggregates: Microscopic Analysis, Mechanical Properties, Drying Shrinkage, and Freeze-Thaw Resistance.” Construction and Building Materials 241 (April 2020): 118129. doi:10.1016/j.conbuildmat.2020.118129.

Shahrajabian, Fatemeh, and Kiachehr Behfarnia. “The Effects of Nano Particles on Freeze and Thaw Resistance of Alkali-Activated Slag Concrete.” Construction and Building Materials 176 (July 2018): 172–178. doi:10.1016/j.conbuildmat.2018.05.033.

Puertas, F., and A. Fernández-Jiménez. “Mineralogical and Microstructural Characterisation of Alkali-Activated Fly Ash/slag Pastes.” Cement and Concrete Composites 25, no. 3 (April 2003): 287–292. doi:10.1016/s0958-9465(02)00059-8.

Mejía de Gutiérrez, R., R. A. Robayo, and M. Gordillo. “Natural Pozzolan-and Granulated Blast Furnace Slag-Based Binary Geopolymers.” Materiales de Construcción 66, no. 321 (January 18, 2016): e077. doi:10.3989/mc.2016.03615.

Silva, Isabel, João P. Castro-Gomes, and António Albuquerque. “Effect of Immersion in Water Partially Alkali-Activated Materials Obtained of Tungsten Mine Waste Mud.” Construction and Building Materials 35 (October 2012): 117–124. doi:10.1016/j.conbuildmat.2012.02.069.

Ismail, Idawati, Susan A. Bernal, John L. Provis, Sinin Hamdan, and Jannie S. J. van Deventer. “Microstructural Changes in Alkali Activated Fly Ash/slag Geopolymers with Sulfate Exposure.” Materials and Structures 46, no. 3 (July 11, 2012): 361–373. doi:10.1617/s11527-012-9906-2.

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DOI: 10.28991/esj-2020-01247


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