Marzieh Kadivar

Due to the increasing interest in bamboo as a construction material, addressing its geometric variation along the culm and the gradient fiber distribution across the wall thickness is essential to develop standardized products for large-scale use. One option is the flattening–densification process, in which the curved material is pressed into prismatic panels that can be stacked and glued in multiple layers. This study assessed the effect of orientation and side arrangement on the physical and mechanical properties of two-layer densified panels, varying both the alignment of fibers (parallel or perpendicular) and the contact face with the adhesive (inner or outer layers with pith ring and skin). After 576 h of water immersion, panels glued in parallel with inner layers facing each other had the lowest water absorption (36.22%), whereas parallel panels glued with outer layers showed higher water absorption and thickness swelling (45.86 and 35.74%, respectively). Flexural strength was greater in parallel-aligned panels, with the highest value observed in the inner–inner configuration (200.3 MPa). The modulus of elasticity of parallel panels (average 20.9 GPa) was up to eight times higher than that of perpendicular panels (average 2.6 GPa). In shear tests, failure occurred along the glue line for parallel panels (up to 7.16 MPa) and by tension perpendicular to fibers in perpendicular panels (up to 5.28 MPa). Scanning electron microscope analysis revealed that adhesive penetration into the bamboo interphase occurred only in parallel panels glued with inner layers, while in other configurations the adhesive remained mostly on the surface (adhesive interphase or bamboo–adhesive interphase). These findings highlight how orientation and layer arrangement govern adhesive penetration and, consequently, the performance of engineered bamboo panels.

As structural engineers face increasing pressure to minimize the embodied carbon of building components, selecting appropriate materials is critical for sustainable design. Thiemission ts study evaluates the life cycle performance of engineered bamboo beams to determine their viability as a low-carbon alternative to traditional timber in structural framing applications. Utilizing OpenLCA software and the Ecoinvent database, a cradle-to-grave analysis was conducted to inform material selection for the Australian construction context. A parametric design study compared two specific bamboo species, Moso and Asper, against traditional Laminated Veneer Lumber (LVL) to identify the optimal material for minimizing environmental impact. The assessment revealed that Asper bamboo beams represent a superior design choice; a 30.74 kg strand-woven functional unit (FU) achieved net-negative emissions of −13.30 kg CO₂e under 2025 conditions. This offers a significant design advantage over traditional LVL options, which are net-positive emitters, and outperforms Moso bamboo, which yielded higher net emissions (+24.60 kg CO₂e) due to lower sequestration rates. Furthermore, dynamic analysis demonstrated the temporal efficiency of this material in the structural life cycle: in the time required for a single Radiata Pine rotation, Asper bamboo completes five growth cycles, storing a net 103.25 kg of CO₂e per functional unit. Confirmed by a sensitivity analysis for robustness, these findings provide quantitative design criteria supporting the integration of Asper bamboo into sustainable building standards and structural specifications.

The natural variability and moisture sensitivity of bamboo limit its widespread use in construction applications. To address these challenges, densification and delignification processes have emerged as promising modification techniques. Densification and delignification processes can lead to significant improvements in the physical, mechanical, and chemical properties of solid wood. In this study, a two-step process of delignification and densification was carried out on Dendrocalamus asper bamboo specimens. The objective was to assess whether the optimized parameters of densification for natural bamboo on an open pressing system can be transferred for delignified bamboo. Delignification was achieved using an alkali solution (NaOH and Na₂SO₃) with two different temperature settings (25 °C or 100 °C). The pre-treated samples were dried in one of the two different conditions, either at 100 °C for 24 h or 25 °C for 30 days, resulting in four different groups with an average moisture content ranging from 7 to 10%. The samples were densified to 50% of their original thickness through an open thermo-mechanical press system at 160 °C with a compression rate of 6.7 mm/min and compared to densified bamboo without delignification (reference). The compression stress required to achieve a 50% degree of densification was evaluated, with untreated samples exhibiting an average value close to 17 MPa. Following treatment, the compression stress ranged from 7 to 13.4 MPa, indicating that the exposure to a high pH solution facilitates the densification process. However, a reduction in flexural properties (MOR, LOP, and MOE) was observed on the alkali-treated samples after a three-point bending test. Physical properties (water absorption and thickness swelling) were not altered after delignification. These findings demonstrate that the direct application of a densification process optimized for natural bamboo is not fully effective for chemically modified bamboo, highlighting the need for adjustments. Delignified bamboo showed an increase in free space after chemical treatment, which should be further densified under higher degrees.

The substitution of fast-growing biogenic materials for high-carbon footprint extractive materials is increasingly discussed as a climate change mitigation tool. This review is based on a comprehensive literature search conducted in Scopus, Web of Science, and Google Scholar databases for publications, focusing on keywords such as “bamboo” and “sustainable construction”. Through this literature and bibliometric analysis, we identify the relative interest in timber bamboo as a sustainable building material and review the carbon-capturing and structural properties that underly bamboo’s growing research interest. However, this has yet to translate into any material degree of adoption in mainstream construction. Given the near absence of subsidies, regulatory mandates, and “green premiums”, timber bamboo must become fully cost-competitive with existing materials to achieve adoption and provide its carbon-mitigation promise. In addition to academic sources, the review draws on the professional expertise of the authors, who have extensive experience in the bamboo industry. Using this expertise, the main problems preventing timber bamboo’s cost competitiveness are analyzed with possible solutions proposed. The combination of rigorous research and industry insights ensures practical applicability. Finally, the beneficial climate prospects of adopting timber bamboo buildings in substitution for 25% of new cement buildings is projected at over 10 billion tons of reduced carbon emissions from 2035 to 2050 and nearly 45 billion tons of reduced carbon emissions from 2035 to 2100.

Despite improving operational efficiency of buildings, annual emissions from construction remain stubbornly high. The substitution of fast-growing biogenic materials for high-carbon footprint extractive materials is increasingly discussed as a mitigation tool. Here we identify the relative interest in timber bamboo as such a tool through literature and biobliometric analysis. We review the carbon capturing and structural properties of timber bamboo that underly bamboo’s growing research interest, which, however, has yet to translate to any material degree of adoption in mainstream construction. Given the near absence of subsidies, regulatory mandates and “green premiums”, timber bamboo must become fully cost competitive with existing materials to achieve adoption and provide its carbon mitigation promise. The main problems preventing timber bamboo’s cost competitiveness are analyzed with possible solutions proposed. Finally, the beneficial climate prospects of adopting timber bamboo buildings in substitution for 25% of new cement buildings is projected at over 10 billions tonnes of reduced carbon emissions from 2035 to 2050 and nearly 45 billion tonnes of reduced carbon emissions from 2035 to 2100.

Densification processes are used to improve the mechanical and physical properties of lignocellulose materials by either collapsing the cell cavities or by filling up the pores, consequently reducing the void volume fraction. This paper focuses on an extensive review of bamboo densification process, which is achieved by compressing the material in the direction perpendicular to the fibers using mainly two different techniques: an open system, thermo-mechanical (TM), or a closed system, viscoelastic-thermal-compression (VTC). The main aim of bamboo densification is to decrease its heterogeneity, as well as to improve its mechanical and physical performance. In addition, densification may occur during the manufacturing of bamboo products in which hot-pressing processes are used to mold bamboo panels. There are over 1600 publications about bamboo, concentrated in the recent decade, mainly about engineered materials. Although several papers regarding bamboo and wood densification are available, very few studies have comprehensively investigated the densification process solely through compression of natural bamboo culms. According to the literature, applying a combination of compression of 6–12 MPa at temperatures between 120–170 °C for 8–20 min can produce materials with higher strength in comparison to the mechanical properties of natural bamboo. The majority of research on bamboo densification indicates that the modified material results in improved properties in terms of density, hardness, bending strength, stiffness, and durability. This paper provides a review that consolidates knowledge on the concept of bamboo culm densification, discusses the roles of parameters that control the process, ascertains the best practice, and finally determines gaps in this field of knowledge.