Radosław Pomykała, Waldemar Kępys, Paulina Łyko
AGH Akademia Górniczo-Hutnicza
This paper describes the tests properties of two-and three-component suspensions, prepared on the basis of fly ashes from the combustion of hard coal in conventional and fluidized bed boilers. The main objective of this study was to determine the effect of temperature on setting time of suspension, which differed in both the type of ash used, the total ratio of solids to water, cement content, as well as its type. Studies on the effect of elevated temperature on the properties of fly ash-water suspensions and ash-water-cement suspensions were taken to determine the behavior of these mixtures under specific conditions characteristic for underground mines, where depending on the location, the temperature can significantly exceed 40°C, and the humidity is maintained at a level close to 100%. Knowledge of the effect of elevated temperature on the setting time of fly ash-water suspensions with the addition of various types of cement may also be useful in other applications, and thus contribute to increase the range and efficiency of combustion by-products utilization. Similar conditions of the seasoning, particularly the temperature 40° C, may be accompanied by the application of suspensions in the surface engineering works, such for example cut-off walls or other type of filter seals. The tests included setting time of suspensions prepared on the basis of fly ash contains desulfurization products (PR) and fly ash from fluidized bed (PF) with 10, 20 and 30% (by weight relative to the weight of solids) addition of Portland Cement (C) or High Alumina Cement (G). The samples were seasoned in standard and elevated temperature conditions. Compositions of mixtures were established at different amounts of ash and water. Based on the test, it was indicated elevated temperature as the most important factor affecting the process of suspensions setting. Using of suspension with the addition of cement, that is, in fact, a binder mixture, should be taken into account that slightly elevated temperature can leading to significantly accelerate the setting process, but simultaneously it can also depend on other factors.
zawiesiny popiołowo-wodne; wpływ temperatury
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