Modelling of transport processes in concrete exposed to elevated temperatures – An alternative formulation for sorption isotherms

• Published in: Cement and concrete research 2018-04, Vol.106, p.144-154
• Main Authors: Davie, C.T., Pearce, C.J., Kukla, K., Bićanić, N.
• Format: Article
• Language: English
• Subjects: ADSORPTION; Adsorption (C); Cement; COMPUTERIZED SIMULATION; CONCRETES; DAMAGE; DRYING; EXPERIMENTAL DATA; FINITE ELEMENT METHOD; FIRES; GENERAL STUDIES OF NUCLEAR REACTORS; GROUTING; High temperature; ISOTHERMS; MATERIALS SCIENCE; Mathematical models; Modeling (E); MOISTURE; Nuclear engineering; Nuclear reactors; Nuclear safety; Physical properties; REACTOR SAFETY; REACTOR VESSELS; Robustness (mathematics); Safety critical; Sorption; Structural damage; Temperature; Temperature (A); TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; Transport processes; Transport Properties (C); WATER
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2018.01.012

There is a significant need to understand, analyse and assess moisture transport in cementitious materials exposed to elevated temperatures in order to confidently predict the behaviour and ultimately the development of damage in safety critical applications such as nuclear reactor vessels, structures exposed to fire and well bore grouts. In view of this need a rigorous and robust formulation to describe water retention curves (sorption isotherms) as a function of temperature based on the evolution of physical parameters is presented. The model formulation is successfully validated against independent sets of experimental data up to temperatures of 80 °C. It is then further validated under isothermal drying conditions and then high temperature conditions through the numerical reproduction of laboratory experiments following implementation in a fully coupled hygro-thermo-mechanical finite element model. The new formulation is found to work well under a variety of conditions in a variety of cementitious material types.