Calorimetry in testing waste materials from the brown coal combustion

Abstract

The calorimetric measurements were applied in testing the wastes collected from different furnaces in electric power plants as materials to be used in civil engineering. The fly ash materials were collected from two power stations based on different brown coal deposits and working with conventional and fluidized bed installation. The reactivity of high calcium fly ash from sub-bituminous coal combustion has been proved in calorimetric, conductometric, chemical shrinkage, and rheological measurements before their practical implementation on larger scale. Highly soluble components of fly ash contribute to the hydration products and structure formation, followed by setting and hardening of fly ash-cement mixture. These results have been the base of research project aimed in the innovative solutions dealing with the management of deposits of wastes generated as a result of coal combustion. The standardization and potential use on larger scale of these materials, necessary from the environmental point of view, seems to be the question of nearest future.

Heat of hydration of low-clinker cements

“…Addition of fly ash more distinctly retards the acceleratory period of cement hydration than slag, this tendency is especially clear for the high substitution rate of fly ashes. This retarding effect of the mineral additions on the cement hydration has been already reported [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35].…”

“…For composite binders containing fly ash, the hydration heat evolution has been studied, inter alia, by Nocuń-Wczelik [25][26][27], Pacewska et al [28][29][30], Giergiczny [31,32], Han et al [22], Kumar et al [33], Narmluk et al [34] and Mounanga et al [35]. Similarly, as for slag cements, the tests showed that the evolved heat decreases with increasing amount of fly ash addition.…”

“…Narmluk et al [34] found that fly ash retards the early hydration of cement but accelerates the hydration of cement in the later period at 20 and 35°C, but at 50°C and 50 % dosage of fly ash retards the hydration of cement at later age as well. Nevertheless, it is highlighted that the influence of fly ash addition on the hydration process can be different and it is dependent on the mineral composition and fineness of fly ash [25][26][27][28][29][30][31][32][33][34][35]. The kinetics and mechanism of hydration in different cementitious systems with fly ash has been also discussed in [25].…”

Partial Replacement of Portland-Composite Cement by Fluidized Bed Combustion Fly Ash

“…Utilization of fly ashes originating from fluidized bed combustion in cement applications has been investigated in several studies (Li et al 2012;Nocuń-Wczelik et al 2014;Pavoine et al 2014;Rajamma et al 2009Rajamma et al , 2015Roszczynialski and Nocuń-Wczelik 2004;Sinsiri et al 2010;Wu et al 2014;Zhao et al 2015). Most of these studies are focused on fly ash from coal combustion and only few (Rajamma et al 2009(Rajamma et al , 2015 on biomass fly ash.…”

Study of pozzolanic action of ground waste expanded perlite by means of thermal methods

“…In this work, the cement-waste expanded perlite mixtures were produced. The kinetics of hydration was evaluated with the help of calorimetric method; this method appeared many times as a best way to obtain basic information dealing with the hydraulic activity of many binders of different origin [7][8][9]. There are some data dealing with the kinetics of heat evolution in cement-natural perlite systems [2], as well as in the waste expanded perlite-cement systems [3].…”