INFLUENCE OF SLAGS OF BOILERS WITH CIRCULATING FLUIDIZED BED ON FROST RESISTANCE OF CONCRETE
Journal Title: Збірник наукових праць Українського державного університету залізничного транспорту - Year 2018, Vol 176, Issue 10
Abstract
The results of the study of the influence of slags of boilers with a circulating fluidized bed on the frost resistance of heavy concrete are presented. In the studies was used fallowing materials: Portland cement PC I-500N, sand with a grain size unit Mkr=1,05, crushed granite fraction 5-10 mm, ashes of boilers with circulating fluidized bed, hyperplasticizer "Fluid Premia-196". The research is conducted using mathematical planning of the experiment. It is proved that with the replacement of sand with ashes, frost resistance is somewhat reduced, but the hyperplasticizer contributes to the reduction of frost resistance by reducing the W/C ratio, resulting in the formation of super-fine pore structure of concrete. Fine pores in the structure of concrete compensate for stress from the process of ice formation at low ambient temperatures. The optimal flow of cement has been established in terms of frost resistance, both by full and partial replacement of sand with ash. It was also determined that the optimum should be considered the consumption of a hyperplasticizer in the amount of 1.2-1.4% of the mass of cement. The introduction of ashes in a concrete mixture leads to a decrease in the frost resistance of concrete. This phenomenon is explained by the fact that the slags have water consumption in three times higher than the amount of sand they replace, therefore they contribute to an increase in the W/C ratio. With the increase in W/C increases both the total volume of open pores, and their average size. At the same time, permeability and water absorption increase and in such concrete less reserve pores are formed. In order to increase the frost resistance of concrete, it is customary to restrict W/C depending on the conditions of concrete service. Reducing W/C is possible, as at the expense of reducing water consumption due to the application of plasticizers additives, and by increasing the cost of cement.
Authors and Affiliations
V. A. Bondar, R. M. Akhmednabiyev, R. R. Akhmednabiyev
Keywords
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- EP ID EP357271
- DOI 10.18664/1994-7852.176.2018.131167
- Views 72
- Downloads 0
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