Abstract:Despite countless use possibilities for bamboo, this material has two major disadvantages. One drawback is the low natural durability of most bamboo species due to presence of starch in their parenchyma cells. The other equally important drawback is the tendency bamboo has to present dimensional variations if subjected to environmental change conditions. In an attempt to minimize these inconveniences, strips (laths) of Dendrocalamus giganteus Munro were taken from different portions of the culm and subjected t… Show more
“…The effects of treatment appear to vary by species. Colla et al [11] explored the impact of heat treatment on Dendrocalamus giganteus Munro, also known as giant bamboo. The authors found that thermal treatment increased the dynamic modulus and modulus of rupture up to 140°C, with additional increase in temperatures resulting in decreased strength and degradation at a micro-scale level.…”
h i g h l i g h t sMechanical characterisation of bleached and semi-caramelised laminated bamboo. Thermal treatment processing methods have an effect on the mechanical properties. Engineered bamboo has mechanical properties comparable to timber.
a b s t r a c tEngineered bamboo is increasingly explored as a material with significant potential for structural applications. The material is comprised of raw bamboo processed into a laminated composite. Commercial methods vary due to the current primary use as an architectural surface material, with processing used to achieve different colours in the material. The present work investigates the effect of two types of processing methods, bleaching and caramelisation, to determine the effect on the mechanical properties. A comparison to other engineered bamboo and timber products is also presented. The results of the study indicate that processing does affect the mechanical properties of engineered bamboo products. Areas in need of further research are also identified for thermally treated bamboo to be used in structural applications.
“…The effects of treatment appear to vary by species. Colla et al [11] explored the impact of heat treatment on Dendrocalamus giganteus Munro, also known as giant bamboo. The authors found that thermal treatment increased the dynamic modulus and modulus of rupture up to 140°C, with additional increase in temperatures resulting in decreased strength and degradation at a micro-scale level.…”
h i g h l i g h t sMechanical characterisation of bleached and semi-caramelised laminated bamboo. Thermal treatment processing methods have an effect on the mechanical properties. Engineered bamboo has mechanical properties comparable to timber.
a b s t r a c tEngineered bamboo is increasingly explored as a material with significant potential for structural applications. The material is comprised of raw bamboo processed into a laminated composite. Commercial methods vary due to the current primary use as an architectural surface material, with processing used to achieve different colours in the material. The present work investigates the effect of two types of processing methods, bleaching and caramelisation, to determine the effect on the mechanical properties. A comparison to other engineered bamboo and timber products is also presented. The results of the study indicate that processing does affect the mechanical properties of engineered bamboo products. Areas in need of further research are also identified for thermally treated bamboo to be used in structural applications.
“…The effect of thermal treatment on Dendrocalamus giganteus bamboo properties was studied [14]. It was encountered that ultrasound velocity (V LL ) was consistently improved (≈ 32 % -38 %) after the treatment up to 260 ºC.…”
Section: Resultsmentioning
confidence: 99%
“…The same method was recently employed to determine dynamic modulus of elasticity of eucalypt treated wood [13]. In another work, it was observed that ultrasound wave velocity was significantly improved in thermally treated bamboo [14].…”
The paper aimed at studying the potential of two nondestructive methods to estimate the wood mechanical properties and mass loss due to thermal treatments. In this study, a low-density tropical hardwood species Simarouba amara (marupá) was used. Forty small beams with dimensions of (25 × 25 × 400) mm (width × thickness × length) were cut from this species. Initially, the beams were nondestructively tested using stress wave and ultrasound methods. Stress wave velocity (Swv), ultrasound velocity (V LL), dynamic modulus of elasticity (E d) and stiffness coefficient (C LL) were longitudinally determined. Afterwards, the beams were thermally treated using a chamber without air circulation under atmospheric pressure. Two schedules were tested: 160 ºC for 180 minutes and 200 ºC for 70 minutes. Mass loss (ML) due to thermal treatment was calculated and the thermally treated material was again nondestructively evaluated. Afterwards, modulus of rupture (f m), modulus of elasticity (E M) and parallel compression strength (f c,0) of treated material were assessed. Backward linear multiple regression analysis was run in order to estimate these properties. Parameters investigated through nondestructive testing (before and after treatment) and derivative variables were used as independent variables, totaling 12 variables. For both treatment schedules, all parameters related to nondestructive techniques were affected by the thermal treatment, thus acoustic velocities and stiffness values were improved. It was found that all evaluated properties of treated material could be modeled at a reasonable level (R 2 = 0.392 to 0.874) depending on the nondestructive method and treatment schedule used. Nevertheless, ultrasound method fitted the most suitable models for a large number of properties. The utilization of variables from both methods together yielded better models whose R 2 value ranged from 0.466 (f m) to 0.941 (E M). It was found that the most important nondestructive variables which entered into the models were: Swv before and after treatment, V LL after treatment, E d before treatment and C LL after treatment. Finally, it could be concluded that stress wave and ultrasound nondestructive methods presented great potential to evaluate properties of thermally treated wood material.
“…Many bamboo species have been investigated for their mechanical behavior after thermal modification. Investigations were done for commercial species from Vietnam (Nguyen et al 2012), Ethiopia (Starke et al 2016), Brazil (Colla et al 2011), China (Zhang 2013), andColombia (Archila et al 2014). Colla et al (2011) treated Asian Dendrocalamus giganteus in inert and non-inert atmospheres for several hours, resulting in improved thickness swelling and stable mechanical properties.…”
Section: Introductionmentioning
confidence: 99%
“…Investigations were done for commercial species from Vietnam (Nguyen et al 2012), Ethiopia (Starke et al 2016), Brazil (Colla et al 2011), China (Zhang 2013), andColombia (Archila et al 2014). Colla et al (2011) treated Asian Dendrocalamus giganteus in inert and non-inert atmospheres for several hours, resulting in improved thickness swelling and stable mechanical properties. Yun et al (2016) investigated Chinese moso Phyllostachys pubescens bamboo and explained the mechanical weakness with changes in crystallinity of bamboo cellulose.…”
Thermal treatments applied to lignocellulosic materials were found to induce internal chemical reactions, which modified the physical and mechanical properties and dimensional stability of the material. A 3-year-old basal section of bamboo (Guadua angustifolia Kunth), with no nodes and no skin, was subjected to a thermal treatment at temperatures which ranged from 160 to 200 °C for 1 to 4 h. The tensile stiffness showed a slight increase with temperature and time, while the tensile strength showed a notable increase at 160 °C for 2 h. There was a 5% difference in the equilibrium moisture content at 80% relative humidity between the untreated samples and the 200 °C, 4 h treatment.
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