Mechanical Properties of Mortars Prepared by Alkali Activated Fly Ash Coming from Different Production Batches

Abstract:

Fly ash is a well utilizable secondary raw material for the production of alkali activated construction materials. It is a significant alumina-silicates source suitable for the chemical reaction resulting in hardened composites. Physical and chemical properties of fly ashes as a co-product of coal burning mainly depend on characteristics of coal, burning temperature and combustion conditions. High variability of the properties of fly ash causes an uncertainty in the properties of alkali activated mortars. Time behaviour of the composition of the fly ash produced in a heating plant located in Košice, Slovakia as well as leaching behaviour of both alumina and silica from particular batches during one-year period was documented. Leaching tests were carried out using the distilled water and alkali solutions with three different concentrations. Both compressive and tensile strengths of alkali activated mortars were measured, and the correlation between the mechanical properties of hardened mortars and the chemical composition of fly ashes as well as their leaching characteristics was investigated.

• Periodical: Solid State Phenomena (Volume 244)
• Pages: 140-145
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.244.140
• Online since: October 2015
• Authors: Matej Špak*, Pavel Raschman
• Keywords: Alkali Activation, Composition Variability, Fly Ash, Leaching, Mechanical Properties

References

[1] M. Špak, I. Halaša, M. Šuster, O. Vojtechovský, Informácie o používaní popolčeka do betónu, BetónRacio, Trnava, (2012).

[2] A. Fernández-Jiménez, A. Palomo, Characterisation of the fly ashes. Potential reactivity as alkaline cements, Fuel. 82 (2003) 2259-2265.

DOI: 10.1016/s0016-2361(03)00194-7

[3] P. Duxson, A. Fernández-Jiménez, J.L. Provis, G.C. Lukey, A. Palomo, J.S. J Van Deventer, Geopolymer technology: the current state of the art. J. Mater. Sci. 42 (2007) 2917–2933.

DOI: 10.1007/s10853-006-0637-z

[4] D. Bondar, C.J. Lynsdale, N.B. Milestone, N. Hassani, A.A. Ramezanianpour, Effectof type, form, and dosage of activators on strength of alkali-activated natural pozzolans, CementConcrete Comp. 33 (2011) 251-260.

DOI: 10.1016/j.cemconcomp.2010.10.021

[5] A. Palomo, M.W. Grutzeck, M.T. Blanco, Alkali-activated fly ashes. A cement for the future. Cement and Concrete Res. 29 (1999) 1323-1329.

DOI: 10.1016/s0008-8846(98)00243-9

[6] A. Buchwald, M. Weil, K. Dombrowski, Evaluation of primary and secondary material sunder technical, ecological and economical aspects for the use as rew materials in geopolymeric binders, in: Proceedings of the 2nd Int. Symposium of Non-Traditional Cementand Concrete, 2005, p.9.

[7] U. Rattanasak, P. Chindaprasirt, Influence of NaOH solution on the synthesis of fly ash geopolymer, Miner. Eng. 22 (2009) 1073–1078.

DOI: 10.1016/j.mineng.2009.03.022

[8] P.W. Ken, M. Ramli, C.C. Ban, An overview on the influence of various factors on the properties of geopolymer concrete derivedrom industrial by-products, Constr. Build. Mater. 77 (2015) 370–395.

[9] C.A. Rees, J.L. Provis, G.C. Lukey, J.S.J. van Deventer, The mechanism of geopolymer gel formation investigated through seeded nucleation, Colloids Surfaces, 2008, pp.97-105.

DOI: 10.1016/j.colsurfa.2007.12.019

[10] A. Hajimohammadi, J.L. Provis, J.S.J. van Deventer, Effect of Alumina Release Rate on the Mechanism of Geopolymer Gel Formation, Chem. Mater. 22 (2010) 5199-5208.

DOI: 10.1021/cm101151n

[11] M. Inada, Y. Eguchi, N. Enomoto, J. Hojo, Synthesis of zeolite from coal fly ashes with different silica–alumina composition, Fuel. 84 (2005) 299-304.

DOI: 10.1016/j.fuel.2004.08.012

[12] P. Duxon, J.L. Provis, Designing Precursors for Geopolymer Cements, J. Am. Ceram. Soc. 91 (2008) 3864-3869.

DOI: 10.1111/j.1551-2916.2008.02787.x