Wastes deriving from FBC plants have been studied in order to assess their capacity of generating, upon hydrothermal treatments, binding products like ettringite, a component characterized by a low density, good mechanical strength and satisfactory water and fire resistance. Due to their composition, mainly composed by lime, calcium sulfate, alumina (ettringite principal components) and silica, FBC waste, generally constituted of two streams, fly and bottom, can be employed, separately and/or together, for the manufacture of ettringite-based light building materials. Two systems, composed, individually, by a fly FBC ash (FAFBC) and a bottom FBC ash (BAFBC), and a third system, constitued by 60% FAFBC and 40% BAFBC, were paste hydrated and cured at 55, 70 and 85°C for periods ranging from 2 hours up to 28 days. Each hydrated system was then submitted to DTA analysis in order to evaluate the curing conditions for enhance the conversion of the reactants towards ettringite. For all the system investigated, It has been found that: (i) the increase of the temperature has a positive effect on the formation rate of ettringite; (ii) a permanence of eight hours at 85°C represents the optimum curing condition. Moreover, FAFBC alone-based mixture exhibits the best hydraulic behavior.
Hydrothermal treatments of FBC waste aimed at obtaining ettringite-based building materials
TELESCA, ANTONIO;CALABRESE, DANIELA;MARROCCOLI, Milena;VALENTI, Gian Lorenzo
2012-01-01
Abstract
Wastes deriving from FBC plants have been studied in order to assess their capacity of generating, upon hydrothermal treatments, binding products like ettringite, a component characterized by a low density, good mechanical strength and satisfactory water and fire resistance. Due to their composition, mainly composed by lime, calcium sulfate, alumina (ettringite principal components) and silica, FBC waste, generally constituted of two streams, fly and bottom, can be employed, separately and/or together, for the manufacture of ettringite-based light building materials. Two systems, composed, individually, by a fly FBC ash (FAFBC) and a bottom FBC ash (BAFBC), and a third system, constitued by 60% FAFBC and 40% BAFBC, were paste hydrated and cured at 55, 70 and 85°C for periods ranging from 2 hours up to 28 days. Each hydrated system was then submitted to DTA analysis in order to evaluate the curing conditions for enhance the conversion of the reactants towards ettringite. For all the system investigated, It has been found that: (i) the increase of the temperature has a positive effect on the formation rate of ettringite; (ii) a permanence of eight hours at 85°C represents the optimum curing condition. Moreover, FAFBC alone-based mixture exhibits the best hydraulic behavior.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
