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Model for heat release of fly ash - cement pastes



Title: Model for heat release of fly ash - cement pastes
Author(s): G. Baert, G. De Schutter, N. De Belie
Paper category : conference
Book title: International RILEM Symposium on Concrete Modelling - ConMod '08
Editor(s): E. Schlangen and G. De Schutter
Print-ISBN: 978-2-35158-060-8
e-ISBN: 978-2-35158-076-9
Publisher: RILEM Publications SARL
Publication year: 2008
Pages: 57 - 64
Total Pages: 8
Nb references: 7
Language: English


Abstract: In the past, isothermal calorimetry has been proposed as an experimental method to predict the hea t development of a Portland cement paste using a reaction degree and an apparent activation energy. Herein, it is assumed that the normalised rate of the reaction only depends on the over-all reaction degree of all clinker minerals together. The influence of the curing temperature is modelled with an Arrheniusfunction. Fly ash can interact with the hydration reaction of one or more clinker minerals: some of these reactions will be accelerated through its presence, while others will be delayed. Depending on the types of fly ash and cement, this can lead to a change in the slope of the isothermal heat rate and even to an additional peak.
On the derivative curve of the heat rate over time, up to six inflexion points can be observed.
Based upon this, the proposal of considering the heat rate as a superposition of several subreactions is investigated. Further research is however needed to investigate whether these reactions can be correlated to real chemical reactions.


Online publication: 2009-06-15
Publication type : full_text
Public price (Euros): 0.00