Modelling of deformations of high strength concrete at elevated temperatures

D. Gawin, F. Pesavento, B. A. Schrefler

Research output: Contribution to journalArticle

77 Scopus citations

Abstract

A constitutive model for the analysis of deformations of concrete subject to transient temperature and pressures is proposed. In these severe conditions concrete structures experience spalling phenomenon, which is the violent or non-violent breaking off of layers or pieces of concrete from the surface of a structural element when it is exposed to high and rapidly rising temperatures. This process can lead to a loss of load-bearing capacity, trough a loss of section and a loss of protection to steel reinforcement. Many different form of spalling exist, but probably the most dangerous is explosive spalling, because it is sudden and capable to result in a general collapse of the structure. The constitutive model includes thermo-chemical and mechanical damage for taking into account the deterioration of the material due to mechanical loads, high temperatures and chemical changes and it is introduced into a general coupled mathematical model of hygro-thermo-chemomechanical behaviour of concrete structures. In this constitutive model the so called free thermal strains, which are the concrete strains during first heating, are decomposed in three main contributions: thermal dilatation strains (treated in a manner usual in thermomechanics), shrinkage strains (modelled by means of the effective stress principle) and thermo-chemical strains (which take into account for the thermo-chemical decomposition of the concrete and which are related to thermo-chemical damage). Thermo-mechanical strains occurring during first heating of concrete under load, known as LITS (Load Induced Thermal Strains), are also included in the framework of thermodynamics of porous media. The proposed model is applied to an illustrative example that demonstrates its capabilities.

Original languageEnglish (US)
Pages (from-to)218-236
Number of pages19
JournalMaterials and Structures/Materiaux et Constructions
Volume37
Issue number268
DOIs
StatePublished - Jan 1 2004

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)
  • Mechanics of Materials

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