WHICH TEMPERATURE-DEPENDENT SORPTION MODELS COULD BE USE TO PREDICT MASS TRANSFERS IN BIO-BASED BUILDING MATERIALS?

Author(s): G. Promis, L. Freitas Dutra1, O. Douzane, A.D. Tran Le, T. Langlet
Paper category: Proceedings
Book title: Proceedings of the 3rd International Conference on Bio-Based Building Materials ICBBM 2019
Editor(s): Mohammed SONEBI and Sofiane AMZIANE
ISBN:
e-ISBN: 978-2-35158-229-9
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 726 - 728
Total Pages: 3
Language: English

Abstract: Hemp and rape straw concretes are bio-based building materials with excellent hygrothermal
behaviour and low environmental impact. Their hygroscopic capacity can improve indoor comfort
by regulating temperature and relative humidity levels through their porous structure. In addition,
they are good insulators being renewable with low embodied energy. This buffering ability can be
expressed by sorption curves, which correlate moisture content at different relative humidities.
However, sorption isotherms vary according temperature reveling the importance of taking into
account heat transfer in sorption phenomena. Since experimentation can be timing consuming
and costly, models have been proposed to estimate sorption isotherms at different temperatures.
Therefore, aiming to accurately model sorption curves considering temperature and hysteresis
influence, this study compares four different temperature-dependent to better describe the
hygroscopic behaviour of bio-based materials. The hysteresis phenomenon is taken into account
by the Mualem II model. Thus, the numerical results from the four temperature-dependent models
implemented in the software COMSOL Multiphysics, were contrasted with experimental
measurements where hemp concrete and rape straw concrete were submitted to cyclic changes
in temperature and relative levels. Results show that, when compared to experimental values, the
hysteresis phenomenon can’t be neglected under some conditions and the modified GAB model
exhibited the best statistical agreement. Poyet and Milly remained

Online publication: 2019
Publication type: full_text
Public price (Euros): 0.00