The outer, epidermal layer of bamboo is rather hard, with a waxy surface. Both the increasing volume fraction of vascular bundles, and the increasing volume fraction of solid within each vascular bundle lead to a pronounced radial density gradient in the bamboo culm, with denser tissue towards the outer part of the culm. The volume fraction of solid in the vascular bundles also increases radially towards the outer part of the culm as the vessels become smaller. A similar, but significantly more gradual, trend is observed along the height of the culm. The volume fraction of vascular bundles increases radially towards the outer part of the culm.
The vascular bundles consist of hollow vessels surrounded by fibrous sclerenchyma cells. The majority of bamboo tissue is a composite of vascular bundles embedded in a matrix of parenchyma cells. The structure of bamboo is considerably more heterogeneous than that of wood. In Moso bamboo, the culm diameter and wall thickness decrease with increasing height on the culm. The culm is divided into sections by nodes that run transversely through the culm cross section the longitudinal sections between the nodes are known as internodes. The bamboo macrostructure consists of a generally hollow cylindrical shoot, known as a culm.
īamboo belongs to the grass family Gramineae ( Poaceae). Bamboo is ready for harvest in less than 10 years and has a greater yield per hectare and higher strength than traditional timber resources. China is one of the leading producers of bamboo Moso bamboo ( Phyllostachys pubescens), the subject of this study, is the most commercially important species in China. According to the FAO's 2010 Forest Resource Assessment, there are 31.4 million hectares of bamboo worldwide, with 60% concentrated in the rapidly developing countries of China, India and Brazil. This study, aimed at increasing the understanding of the structure–property relationships for Moso bamboo, is part of a larger project that includes work on processing of SBPs, on the structural, thermal and moisture performance of SBP, and on life cycle assessment.īamboo is an abundant, sustainable resource. The use of SBPs is currently limited by the lack of material property data and appropriate building codes. Recently, there has been increasing interest in engineered structural bamboo products (SBPs), analogous to engineered wood products such as plywood and glue-laminated timber. Traditional bamboo structures use entire culms for framing and woven mats for panelling. This work contributes to critical knowledge surrounding the microstructure and mechanical properties of bamboo, which are vital to the engineering and design of sustainable SBPs.īamboo has been used as a structural material for millennia. Compared to common North American construction woods loaded along the axial direction, Moso bamboo is approximately as stiff and substantially stronger, in both flexure and compression but denser. Based on the microstructural variations (observed with scanning electron microscopy) and extrapolated solid cell wall properties of bamboo, we develop models, which describe the experimental results well. Here, we measure the flexural properties of Moso bamboo in the axial direction, along with the compressive strengths in the axial and transverse directions. The radial and longitudinal density gradients in bamboo give rise to variations in the mechanical properties. In this study, the properties of natural Moso bamboo ( Phyllostachys pubescens) are investigated to further enable the processing and design of SBPs. These SBPs are analogous to wood products such as plywood, oriented strand board and glue-laminated wood. Although bamboo has been used structurally for millennia, there is currently increasing interest in the development of renewable and sustainable structural bamboo products (SBPs).
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