Strain of heated concrete during two thermal cycles. Part 3: isolation of strain components and strain model development

This paper follows on from the two previous papers in the series dedicated to the strain behaviour of three nuclear reactor type concretes during a 14-day two-thermal cycle. While the trends were described in detail in the previous papers, the present paper is dedicated to the separation and quantification of strain components during the various stages of the heat cycles in order to develop a predictive strain model for use in finite element modelling. The total strain is shown to be the superposition of individual strain components, each related to the specific strain inducing mechanism within the concrete. Having established the principles of strain components, the strains measured during the first thermal cycle under load were isolated, and quantified, according to the strain type and heating stage: (a) virgin heating under load: load-induced thermal strain (LITS) and shrinkage components; (b) constant temperature: creep, shrinkage and crack-induced strain; and (c) cooling: contractive thermal strain, ...