A review of the long-term effects of humidity on the mechanical properties of wood and wood-based products

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A review of the long‑term effects of humidity on the mechanical properties of wood and wood‑based products Juan Wang1,2 · Xiaoqing Cao1,2 · Haojin Liu1 Received: 11 December 2019 / Accepted: 2 November 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract Wood is an indispensable building material for modern structures. As a kind of biological material, it is more likely than other materials to be affected by the environment. It has been shown that the effect of long-term exposure to humidity will accelerate the decrease in mechanical properties and long-term strength of wood and wood-based products. The most commonly used methods for studying the deterioration of the mechanical properties of wood and wood-based products under the action of long-term humidity exposure are artificially accelerated aging and outdoor exposure. Many scholars have studied various artificially accelerated aging tests, which can accelerate the aging of wood and wood-based products and save substantial time. However, the results of outdoor exposure tests can be better correlated with the aging of the materials in the actual environment. Scholars have established a relationship between artificially accelerated aging tests and the results of outdoor exposure tests and have studied the results of outdoor exposure tests under different climatic conditions. This paper not only reviews the artificially accelerated aging tests used for wood and wood-based products in the past twenty years, but also summarizes their characteristics and application scope. In addition, the relationship between the outdoor exposure tests and the artificially accelerated aging tests is reviewed. At the end of the paper, the challenges and prospects for the future works are put forward.

1 Introduction In recent years, modern wood structures have gradually entered the public consciousness because of their environmental protection characteristics, good heat preservation and energy savings, good seismic performance and short construction cycle. As an assembled architectural form, modern wood structures have a history of more than 100 years. Modern wood structure mainly includes pure wood (log) structure, glued wood (glulam, cross laminated timber (CLT), laminated veneer lumber (LVL), etc.) structure and mixedwood structures (steel-wood mixed, concrete-wood mixed, etc.). As biological materials, wood and wood-based products are an indispensable part of modern wood buildings and are more vulnerable to environmental influences. Here, wood refers to wood members made by simply processed * Juan Wang [email protected] 1



School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China



Beijing’s Key Laboratory of Structural Wind Engineering and Urban Wind Environment, Beijing 100044, China

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logs and wood-based products including glulam, CLT, LVL, plywood, particleboard, fiberboard, oriented strand board (OSB), etc. In particular, long-term exposure to humidity changes will not only accelerate the deformation of w