Durability of autoclaved aerated concrete produced from fluidized fly ash

• Autorzy: Drabik M. , Balkovic S. , Peteja M.
• Konferencja: 5th International Conference on Autoclaved Aerated Concrete "Securing a sustainable future" to be held at Bydgoszcz to celebrate 60 years of AAC experience in Poland, Bydgoszcz, September 14-17, 2011
• Języki publikacji: PL

Abstrakty

EN

The properties of autoclaved aerated concrete (AAC) formed with the utilization of modified raw materials - new generation of fly ash from coal power plants (fluidized fly ash) were studied. The fluidized fly ash is a mixture of bed material and fly ash in the ratio 2:1. The high content of CaSO4, CaO and clay minerals (illit, diaspor) has been proved during the chemical and phase composition investigations. The fluidized fly ash was used as 0%, 30% and 100 % component of the raw mixture respectively. The AAC produced commercially (with fly ash from classical combustion) was used as reference material. The results of long-range experiments, aimed at the durability characteristics within the three years tests, are comprehensively discussed. The strength of samples decreases with the addition of fluidized fly ash, the lowest values are exhibited by samples with 100 % fluidized fly ash content in the raw mixture. The X-ray analysis, TG and OTA, IR spectroscopy, electron microscopy and EOX spectroscopy have been employed. Both phase analysis and strength data show the higher tendency of samples with fluidized fly ash towards the thaumasite formation, being the result of partial conversion of hydraulic C-S-H and tobermorite-Iike phases to nonbinding thaumasite. However, the expansion of tested samples resulted from the formation of thaumasite, as well as gypsum and ettringite in AAC, does not imply the deterioration on such a scale as observed in the concretes. The difference is due to the porosity and pore structure in AAC, developed as a result of air drying. These data contribute also to the discussion of topics of thaumasite formation vs. thaumasite sulfate attack. The results represent a basis of the proposals of modified production of AAC.

Słowa kluczowe

PL

beton komórkowy; popiół lotny fluidalny; trwałość; skład fazowy

EN

autoclaved aerated concrete; fluidized fly ash; durability; phase composition

• Wydawca: Fundacja Cement, Wapno, Beton
• Czasopismo: Cement Wapno Beton
• Rocznik: 2011
• Tom: nr spec.
• Strony: 29--33
• Opis fizyczny: Bibliogr. 7 poz., il.

Twórcy

autor

Drabik M.

autor

Balkovic S.

autor

Peteja M.

• Institute of Inorganic Chemistry Slovak Academy of Science, SK-845 36 Bratislava, Slovakia,

Bibliografia

• [1] Balkovic S., Peteja M. and Drabik M 2010. Long-term Studies of autoclaved aerated concrete produced from fluid fly ash. Proc. of XIV. conference on Ecology & new building materials and products (Telč, Czech republic), pp. 133-136.
• [2] Barnet, S.J., Macphee, D.E., Lachowski, E.E. and Crammond, N.J. 2002. XRD, FDX and IR analysis of solid solutions between thaumasite and ettringite. Cement & Concrete Research, 32, 719-730.
• [3] Bensted J., Varma S. P. 1974. Studies of thaumasite - Part II. Silicates Industrieles39 (1), 11-19.
• [4] Drabik M., Tunega D., Balkovic S., and Fajnor V. S. 2006. Computer simulations of hydrogen bonds for better understanding of the data of thermal analysis of thaumasite. Journ. Of Thermal Analysis & Calorim. 85, 469-475.
• [5] Matsushita F., Aono Y. and Shibata S. 2000. Carbonation degree of autoclaved aerated concrete, Cement & Concrete Research 30, 1741-1745.
• [6] Mróz R., Gawlicki M. and Malolepszy J. 2007. The sulfate corrosion of mortars containing FBC Ash. Prac. of 12th International Congress on the Chemistry of Cements (Montreal), T 4-06.5, pp. 1-12.
• [7] Skalny J., Marchand J., and Odler I. 2002. Sulfate Attack on Concrete, E&FN Spon. London, New York, Sections 4, 5 & 8.