Durability and Mechanical Performance of Differently Treated Glulam Beams during Two Years of Outdoor Exposure

Abstract

The performance of the composites is influenced by the service life of input raw wood material and used adhesives. The aim of the study was to assess the durability and mechanical performance of glulam beams treated in a different way (thermally modified and/or treated with copper-based wood preservative) and exposed in an outdoor application. Glulam beams (83 mm × 68 mm × 1100 mm), made of three layers of Norway spruce (Picea abies) with PUR adhesives used have been exposed in use class 3.2 in a horizontal position since 4th November 2016. Part of the specimens was equipped with MC sensors. Every year, the degradation was evaluated visually. The dynamic modulus of elasticity was determined by longitudinal vibration, and the static modulus of elasticity using a 4-point bending test. On the smaller specimens, cut from glulams, compressive strength, delamination, and shear strength of adhesive bonds were determined. After two years of exposure, the results indicate that the performance of glulams is determined by the wood modification and applied wood preservative.

Effect of Layers Number on The Bending Properties of Chestnut Glulam Beams

“…They discovered that the results were good. The mechanical characteristics of three-layer glulam beams (83 × 68 × 1100 mm) manufactured of Norway spruce were examined by Kržišnik et al (2020). Research has indicated that in the case of untreated samples, after two years of exposure to the outdoors, some faint indications of fungal decomposition were seen.…”

Mechanical Performance of Heat-Treated Norway Spruce (Picea abies) Wood

“…Nowadays, non-biocidal solutions are preferred, and various biocide-free modifications are available on an industrial scale [10]. One well-established technique is thermal modification or heat treatment [11]. According to data from [13], Europe produces up to 530,000 m 3 of heattreated (HT) wood annually.…”

The Effect of Storage Conditions on the Strength Characteristic of Glulam Beams

“…According to Ansell [17], at the beginning wood-based composites were predominantly used for indoor applications; however, nowadays they are frequently seen in outdoor applications exposed to changing weather conditions as well [18]. In addition to changing ambient humidity, GLT stored outdoors is also susceptible to weathering process and degradation by fungi, which can significantly affect the mechanical characteristics of structural beams [19][20][21].…”