The utilization of fly ash in concrete as partial cement replacement has many benefits. It leads to increase of a binder´s amount and improves workability (pumpability, keepability and others) of fresh concrete, as fly ash behaves as a solid fluidifier. Application of fly ash in combination with a fluidifier is very effective, because it improves the workability of fresh concrete significantly. Regarding characteristics of lower class fresh concrete the main benefit of fly ash utilization with fluidifier is complement of fine binder, especially particles up to 0,25mm. At the same time, fly ash hinders segregation and flowing of very soft and liquid fresh concrete (cone consolidation 100 mm and more) contributes to the higher structure homogeneity and higher quality of concrete construction surfaces. The phases of hydrate created in pozzolanic reaction cause higher strength of fly ash mixtures, structure concretion, and finer porosity.
However, results of our research of mechanical properties of fly ash – concrete composites by various chemical (plasticizers and aeration) additives showed deviations in the resulting strengths. The aim of this paper is monitoring of these deviations by the X-ray fluorescence method and thermal analysis and their subsequent evaluation.
1. Rawshan, A.B, S.K. Satari and J.J. Pereira, 2010. Waste generation and recycling: Comparison of conventional and industrialized building systems. Am. J. Environ. Sci., 6: pp. 383-388.
2. Kumaran, G.S., N. Mushule and M. Lakshmipathy, 2008. A review on construction technologies that enables environmental protection: rubberized concrete. Am. J. Eng. Applied Sci., 1: pp. 40-44.
3. Myle, N. J, Wonchang, Ch. and Taher, A. L., 2011. Use of Recycled Aggregate and Fly Ash in Concrete Pavement. American J. of Engineering and Applied Sciences 4 (2), 2011, pp. 201-208, 2, ISSN 1941-7020.
4. Yazici, S., Arel, H. S., 2012. Effects of fly ash fineness on the mechanical properties of concrete, Sadhana, vol. 37, part 3, 2012, pp. 389–403.
5. Goldman A and Bentur A 1993 The influence of microfiller on enhancement of concrete strength. Cement and Concrete Res. 23: 962–972.
6. Aiqin W, Chengzhi Z and Wei S 2003 Fly ash effects: I. The morphological effect of fly ash. Cement and Concrete Res. 3: 2023–2029.
7. Chindaprasirt P, Chai J and Sinsiri T 2005 Effect of fly ash fineness on compressive strength and pore size of blended cement paste. Cement and Concrete Res. 27: 425–428.
8. Toutanji H, Delatte N, Aggoun S, Duval R and Danson A 2004 Effect of supplementary cementitious materials on the compressive
strength and durability of short-term cured concrete. Cement and Concrete Res. 34: 311–319.
9. Ondova, M., Stevulova, N., Estokova, A., (2012). The Study of the Properties of Fly Ash Based Concrete
Composites with Various Chemical Admixtures. Procedia Engineering 42, 2044-2054.
10. Parrott, L.J., Killoh, D.C., (1989). Carbonation in a 36 year old in-situ concrete, Cem. Concr. Res. 19, pp. 649–656.
11. Platret, G., Deloye, F.-X.,(1994). Thermogravimetry and carbonation of cements and concretes, Actes des Journées des Sciences de l'Ingénieur du réseau des Laboratoires des Ponts et Chaussées, Publication LCPC, Paris, pp. 237–243, (in French).
12. Lam, H. K., Barford, J. P., McKay, G., (2010). Utilization of incineration waste ash residues as Portland cement clinker. Chemical Engineering Transactions 21, 757-762.
13. Ondova, M. et al., (2012). Assessment of selected indicators of portland cement containing fly ash in road concrete. Journal of Interdisciplinary Research 2, 114-116.
14. Villain, G., Thiery, M., Platret, G., (2007). Measurement methods of carbonation profiles in concrete: Thermogravimetry, chemical analysis and gammadensimetry. Cement and Concrete Research 37, pp.1182–1192.
15. Sauman, Z., (1971). Carbonization of porous concrete and its main binding components. Cement and Concrete Research 1, 645-662. 16. Thiery, M., Villain, G., Dangla, P., Platret, G, (2007). Investigation of the carbonation front shape on cementitious materials : Analysis of the effects of the chemical kinetics. Cement and Concrete Research 37, 1047-1058.