1. Creep properties of heat treated wood in radial direction. Université Montpellier 2 - CNRS Laboratoire de Mécanique et Génie Civil Equipe Mécanique de l’Arbre et du Bois PhD student Julien COLMARS Museu D. Diogo de Sousa, Braga, Portugal, 5-7 November 2008 Parallel session 2 (WG2) Strength of Aged Load Bearing Structures // POSTER N° 8

2. Introduction Background: Heat treatment was used in previous studies as an ‘accelerated ageing’ and showed so far good results on different softwood with respect to the darker color, fragile behavior and the improved stability against humidity changes. Our objective: Determine the effect of heat treatment on creep behavior of hardwood, such as Poplar wood, in transverse direction (literature is mainly focused on longitudinal direction). These choices were motivated by our previous work on panel paintings (COST IE0601 Florence 2007). Host institute & Funding: This study was conducted in Kyoto University thanks to the Japanese Society for Promotion of Science (JSPS).

3. Thickness 1.6mm Width 10mm Length 60mm Saturated solutions: Relative Humidity 11,22,43,53,62,75,84,92,97% at 24°C 10 days conditioning Heat treatment (150°C, 24 hours) No treatment Sorption Isothermes Material & Method Creep tests on Italian Poplar samples in Radial direction 3 points bending Creep Tests (10 hours) At constant humidity (22,62,84,92,97%)

4. Discussion Influence of moisture content in service (even constant mc%) on creep behavior of both treated and untreated poplar. Chemical modification of wood during heat treatment and its effects on creep properties. Discussion about post treatment methods for analyzing the results (Time response spectrum, Approximate Complex Plane…). Special Acknowledgements: To Miyuki MATSUO and Misao YOKOYAMA from RISH (Kyoto University) for the discussions about heat treatment. Thanks to Luca UZIELLI for providing the material of this study, and Bertrand MARCON for preparing and deliver it...

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