Preliminary Study on Bonding Integrity of Tropical Hardwoods Cross Laminated Timber Manufacturing by Vacuum Pressure Method

Abstract

AbstractCross laminated timber (CLT) is known as a composite material that possesses high-performance properties. As an engineered timber product, it has been proven that CLT has better properties in terms of its strength compared to solid sawn timber. However, the strength of this product is influenced by its bonding integrity. To date, the production and performance of CLT from tropical hardwood is still less known. A lot more studies need to be explored especially on bonding integrity that contributes to CLT’s strength efficiency. High temperature and humidity as well as the uniqueness of the tropical anatomical structure of hardwood significantly affected this bonding integrity. Therefore, preliminary study is conducted under laboratory scale before the manufacturing is executed in industrial scale. In this study, the bonding integrity of the CLT panels from tropical hardwood namely, Light Red Meranti and Keruing are assessed. The CLT panels are manufactured via semi-scale of vacuum press for three and five layers with dimensions of 1.3 m length × 1 m width in accordance with EN16351. Block shear are carried out in this bonding integrity study. A total number of 189 test samples were taken at various locations from these panels to represent the entire CLT panel. Four type of treatments are provided to simulate various service conditions, which are dry, wet, wet + re-dry, and delamination (induced pressure) environments. All designed tests are conducted in accordance with EN16351 and EN14374. The characteristic value of shear strength and wood failure percentage (WFP) were measured. From this study, the bonding performance of Light Red Meranti shows the good bonding performance compared to Keruing.KeywordsBonding integrityCross laminated timberTropical hardwoodsVacuum pressure method