Aging Effects on Flexural Behavior of Glass Fiber-Reinforced Stone-Cork Composite Panels for External Facade Elements

Abstract

Highlights: What are the main findings? Bending strength and failure modes were unaffected by aging. Aged specimens exhibit reduced flexural stiffness and lower shear rigidity relative to unaged samples. What are the implications of the main findings? Durability in terms of strength is promising. The stability of bending strength after aging suggests that the composite retains its load-bearing capacity over time, making it suitable for long-term applications. Consistent failure mechanisms improve predictability. The unchanged failure modes between aged and unaged samples support reliable modeling and structural assessment across the composite’s lifespan. The building sector faces sustainability issues due to its substantial resource demand, prompting the exploration of alternative materials of natural origin. Given the diverse environmental conditions buildings experience, assessing the impact of these conditions on the mechanical characteristics of alternative materials becomes crucial. This study focuses on a composite comprising stone, agglomerate cork core and glass fiber-reinforced epoxy skins, designed for ventilated facades. The composite underwent an aging cycle commonly applied in the evaluation of construction building materials to evaluate its flexural behavior. To that end, bending tests on unaged and aged samples were carried out to investigate both the bending strength and stiffness. The composite panels were tested in two configurations: (i) stone facing up and (ii) stone facing down. The results indicated that higher bending strength was found in samples where the stone was facing up, regardless of the aging condition. In the stone facing up configuration, the predominant failure mode was stone crushing, whereas the samples in the stone facing down configuration evidenced a failure mechanism of fiber breakage. Despite the observed morphological differences between aged and unaged specimens, no significant difference was found regarding the bending strength and failure modes in both tested configurations. However, a flexural stiffness reduction of at least 21% was found for every aged specimen.