The present study has been divided into two parts. At first, the different shear test methods mentioned in the ISO and ASTM Standards such as the direct shear test and the bowtie shear test were presented and compared to a method proposed by the authors so-called the interlaminar shear test method, to suggest an easy, reliable, and feasible way to measure the bamboo shear strength. At the interlaminar shear test method, a shear surface is created by using bamboo strips with two notches/cuts at two opposite sides. By changing the distance of the cuts and bamboo width, the variation of bamboo shear strength based on these two parameters was studied. The FEM modeling by ANSYS and the DIC (Digital Image Correlation) test were carried out to show the shear stress and strain variation alongside the shear surface of interlaminar samples. The different test methods show the results of direct and bowtie test methods are close to each other but different from the interlaminar test method. In conclusion, a comparison has been made between these three shear test methods. In the second part of this investigation, the interlaminar shear test method was chosen for the heat-treated samples. Shear tests were performed on specimens previously heated during either 3 or 24 h at each of six temperatures in the range of 100-225 degrees C. The first significant reduction in the shear strength was observed after heat treatment at 150 degrees C for 24 h and 175 degrees C for 3 h of heat exposure.

Bamboo (Dendrocalamus giganteus) is a functionally graded material with well-organized hierarchical structures. Its micrometer-sized vascular bundles and parenchymatic living cells allow an efficient upward flow of water and nutrients, endowing the organism with remarkably fast growth. As demonstrated recently, the hollow microstructure channels can be explored as a natural template for microfluidics applications in chemical synthesis, analytical detection, solar steam generation, and electrochemical devices. Thus, the knowledge of the kinetics of the imbibition and spatial distribution of fluid through the microcavities of the bamboo vegetal tissue became of interest. Here, we employed a combination of X-ray microtomography (µCT) and proton time-domain NMR (TD-NMR) to identify, measure, and investigate empty volumes embedded in the bamboo’s tissue as experienced by different organic and inorganic fluids, namely dimethyl sulfoxide (DMSO) and distilled water (H2O). Results have shown that the extensive communication between the voids (parenchymal cells and vascular channels) does not prevent the individuation of fluid reservoirs with different behaviors, as evidenced by the H2O desorption profile. Bamboo parenchyma was the tissue that retained more residual H2O after desorption. The difference in wettability of bamboo tissues by DMSO and H2O was detected.

Bamboo, like wood, is a promising natural template for biobased devices that takes advantage of its hierarchical architecture, microarray channels, anisotropic mechanical and electrical properties. Herein we report a low heat thermal treatment (HTT, 700-1000 degrees C) of natural bamboo specimens to obtain bamboo-based graphitic devices with thermoelectric and electrochemical properties. The preservation of the highly anisotropic architecture of three-dimensional carbon material (3D-CM) allowed adding specific thermoelectric and electrochemical prop-erties depending on the HTT of the pristine specimens. High electric conductivity (a, 839 S/m) was observed at 1000 degrees C showing a remarkable potential application as a bamboo-based working electrode. The bamboo annealed to 700 degrees C showed higher resistivity (p, 0.15 & omega; m, and a, 6.6 S/m), thermal conductivity (1.77 W/m K), and thermal heating rate (1.0 degrees C/s). The pyrolyzed biomass (B-700) was used as a 3D microfluidic heater to heat polar solvents (H2O and ethylene glycol) in flow mode up to their boiling points. A 2D carbon hotplate heater was built-up to warm solvent in batch mode. A complete chemical and physical characterization of the samples allowed us to determine structural and chemical compositions, cellulose crystalline structure phase transition to graphitic/turbostratic carbon, thermal and electrical conductivity of unprecedented bambootronics bio-devices.

Bamboo is a sustainable material with a high potential to replace high-contaminating materials such as steel and concrete in many uses. However, some properties, such as the resistance to pests and dimension stability, must be improved for bamboo to be accepted by the engineering community. A low-cost way to improve dimension stability and resistance against pests is to expose the material to heat. This paper presents the results of an investigation on the effect of heat exposure on the mechanical properties of Dendrocalamus giganteus (DG) bamboo. The mechanical tests were performed to specimens previously heated during either 3 or 24 h at each of six temperatures in the range 100-225 degrees C. The mechanical characterization included axial and transverse tensile experiments, axial compression, and non-destructive dynamic tests to determine the dynamic flexural modulus (DFM). The effect of moisture content on mechanical properties was also measured by using untreated specimens at dry and at equilibrium moisture content (EMC) conditions. The different moisture content of the specimens from dry to EMC did not change the ultimate tensile strength (UTS), while the difference between ultimate compression strength (UCS) at EMC and dry conditions was significant and this result shows the remarkable influence of the matrix mechanical properties on the UCS. A tangible reduction in UTS and ultimate transversal tensile strength (TUTS) occurred at temperatures higher than 150 degrees C while the DFM was not reduced significantly and nearly remained the same for specimens heated during 3 hat temperatures lower than 200 C. Results of this study can be taken as guidelines to plan heat exposure cycles intended to improve the dimension stability and pest resistance of the raw material as well as to assess changes in the mechanical properties during the manufacture of products such as densified bamboo.

• Following the principles of low-cost, energy saving, low polluting and sufficient thermal, humidity and acoustic insulation of soil blocks as a construction material, there is an increasing interest to study clay adobe elements. This study presents a mathematical model for predicting the relationship between uniaxial compressive stress and corresponding strain which can be useful for simulating the structural behavior of plain and short fiber reinforced adobes with concrete damage plasticity model in ABAQUS. In this direction, the compressive properties of four different plain and short fiber reinforced adobes was measured in experimental tests. From the obtained results, the essential parameters of the stress-strain curves for all various mix design specimens were extracted for numerical modeling. By a statistical study on the various results of compressive tests as available in the related literature, the proposed equations were developed for predicting the necessary parameters when the only needed experimentally determined parameter is the peak compressive stress. The suggested model is compatible with the behavior of different adobes with different composition, compacting, curing and testing condition. • The recommended model and formulations are to some extent more successful in predicting the linear and nonlinear behavior of different adobes according to other models.• Finally, a mathematical model is developed for predicting the inelastic range of the compressive stress-strain curve.

Self-supporting bamboo structures are ultralight architectural modules applying bamboo round poles, tensile pantographic grids and textile membranes. The structural system applies articulated flexible joints in polyester ropes and locking bio-composite bandage rings, keeping bamboo bars free of torsion stresses. An experimental 1:3 scale prototype and a full-scale structure were fabricated to make previsions about the physical and mechanical behavior of the structure. The experimental results were verified applying a numerical model for the structure. In turn, the flexible joints were analyzed theoretically. The computer model was analyzed using the finite element SAP2000 program. The numerical results were in close agreement with the experimental results specifically for the structural behavior of the flexible joints.

The objective of the present investigation is to study the static and dynamic flexural behavior of bamboo as a functionally graded material to determine the Static Flexural Modulus (SFM) for untreated bamboo samples and to evaluate the effect of heat on the variation of the Dynamic Flexural Modulus (DFM). For the static flexural test, initially, the image processing has been carried out to establish the fiber distribution equation along the radial direction followed by the use to measure the tensile and compressive modulus of elasticity (MOE). The result of static flexural tests shows four different values of MOE at tensile and compressive state for inner and outer bamboo walls with low and high fiber density respectively. The average of the MOE at the tensile is circa 12% higher than in its compressive state. A non-destructive method, based on the impulse excitation technique is proposed for the heat-treated specimens to establish the DFM. The effects of different temperatures and time exposures as well as moisture content, on the DFM and weight of the specimens, have been considered in this study. Comparing the static and dynamic test results for untreated bamboo does not show a meaningful difference between SFM and DFM. The dynamic flexural test shows the effect of heat treatment on DFM to be less than 6% when heated for 3 h at 200 degrees C or when heated at 175 degrees C for 24 h.

Due to its reliability, strength, and ease of access, bamboo has become an attractive material for engineering applications. However, heterogeneous properties and durability issues still hinder the widespread use of bamboo as a building material. Thermo-mechanical treatment is a method to decrease the heterogeneity of bamboo culms and enhance mechanical properties and durability, but it may negatively impact dimensional stability. The objective of this study was to achieve the minimum spring back, water absorption, and thickness swelling for densified bamboo. Accordingly, the behavior of bamboo samples subjected to different thermo-mechanical (TM) treatments using a two-step analysis was investigated. In the first step, the optimum TM treatment for achieving the highest critical densification degree (DD) without shear failure was determined. In the second step, the three key elements of dimensional stability were studied for this optimum case. According to the first step results, the maximum achievable DD in which no shear failure happens and the texture is not disturbed is about 43.6%, and it can be obtained at 200 degrees C with a compression rate of 2 mm/min. X-ray densitometry analysis confirmed that DD of around 50% achieved the highest value of density, 1.30 g.cm(-3). The results of step 2 revealed that the lowest values of spring back, water absorption, and thickness swelling, 4.72%, 23.80%, and 17.70% respectively, for densified bamboo occur when the densification process is conducted at 200 degrees C and adopting a compression rate of 6.7 mm/min. In conclusion, by manipulating and optimizing process parameters, the dimensional stability and final quality of densified bamboo can be improved, opening new opportunities for this class of material. (C) 2021 Elsevier Ltd. All rights reserved.

Bamboo-based devices! A new method to fabricate silver conductive coatings into the inner walls of bamboo vascular bundles is disclosed. The hollow conductive microchannels enabled the development of new electrical and electrochemical devices.

The understanding of sustainability in building construction has undergone changes over the years. First, attention of specialists was directed towards the topic of limited resources, especially energy and its impact on the natural environment. Now, emphasis is placed on technical issues such as materials, building components, construction technologies and energy-related design concepts, as well as on nontechnical issues such as economic and social sustainability. The pursuit of sustainable development as defined by Brundtland et al. in 1987 as ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’ has become a major issue when trying to meet the challenge of providing proper housing for an increasing world population. To increase understanding of sustainable materials, also known as nonconventional materials and technologies using organic materials, which are used either alone or as reinforcement in different types of matrices such as soil, cement and polymers, many research programmes summarized in this book have been carried out all over the globe. Indigenously available local materials such as bamboo, vegetables fibres, soil, quick lime and nonconventional cement mortar materials are used in the production of new structural elements. Bamboo is applied in space structures, corrugated sheets made of cement mortar composites, soil–fibre composites for load-bearing walls and concrete elements are reinforced with organic fibres such as sisal, jute, curauá, pupunia, piassava and coconut fibres. This chapter presents a concise summary of preindustrial materials and technologies, travelling in time to review the development of sustainable composites using organic local materials, such as bamboo, as structural elements in addition to the production of cementitious and soil composites reinforced with vegetable fibres. Finally, some recommendations for future studies are proposed in the hope that newly developed nonconventional materials might better contribute to sustainable development.

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.

Uncontrolled population growth and disorderly urban development have witnessed severe human settlement damages worldwide. Extreme natural phenomena consequence of abrupt climate change such as intense rainfall index increment has provoked landslides incidents hardly to ignore over the last decades. Piles made of conventional materials such as timber, steel and concrete have traditionally been used for slope stabilization in order to prevent landslides incidents. The present paper studies the use of a non-conventional material, the bamboo of the Dendrocalamus Giganteus (DG) species as bamboo-pile for slope stability, to become a more environmental friendly pile material alternative. Its dimensions and more importantly its mechanical properties, besides its geographical availability and greenhouse gases absorbing capabilities make it suitable for an ecologic slope stabilizing pile element. Finite Element Method (FEM) analysis of bamboo-pile was developed on PLAXIS software for 2 and 3 dimensional tests. An unstable slope model condition was reinforced with bamboo-piles to observe the soil-pile interaction and evaluate the safety factor (SF). The results showed that the capabilities of the bamboo-piles are a promising effective alternative for slope stability.

In this investigation, bamboo ( Dendrocalamus giganteus Munro) timbers were coated selectively into vascular vessel bundles with a potential antimicrobial colloidal solution of silver nanoparticles (Ag-NPs). Electric charge and size of Ag-NPs, with different charged organic ligands (trisodium citrate and chitosan), affect their self-sorting in different anatomical structures of bamboo when submitted up to 20 impregnation cycles through a vacuum system. Physicochemical characterization of Ag-NPs was performed by spectroscopic techniques and electron microscopy. Confocal laser scanning microscopy and scanning electron microscopy were employed to characterize natural bamboo. Qualitative and quantitative determination of the metal coating in bamboo specimens was performed with X-ray microtomography (μCT), energy-dispersive X-ray spectroscopy, and X-ray diffraction. μCT revealed a gradient deposition of citrate-capped Ag-NPs into the parenchyma tissue with the higher concentration at the outer part of the bamboo. On the other hand, the chitosan-capped Ag-NPs were deposited mainly in the vessel bundles.

The fabrication of a new copper-functionalized lignocellulosic microreactor (Cu-LμR) from bamboo culms is herein described together with its operation to perform a copper(I)-catalyzed 1,3-dipolar cycloaddition between azide and terminal alkyne (CuAAC). The bio-microfluidic device showed an easy prototyping and fast functionalization with copper ions. All reactions were carried out in flow regime with aqueous-methanol solvent and minimal leaching of copper, yielding a series of model 1,4-disubstitued triazole derivatives with good efficiency in a low-resource setting.

Purpose The purpose of this paper is to provide a method to predict the situation of a loaded element in the compressive stress curve to prevent failure of crucial elements in load-bearing masonry walls and to propose a material model to simulate a compressive element successfully in Abaqus software to study the structural safety by using non-linear finite element analysis. Design/methodology/approach A Weibull distribution function was rewritten to relate between failure probability function and axial strain during uniaxial compressive loading. Weibull distribution parameters (shape and scale parameters) were defined by detected acoustic emission (AE) events with a linear regression. It was shown that the shape parameter of Weibull distribution was able to illustrate the effects of the added fibers on increasing or decreasing the specimens’ brittleness. Since both Weibull function and compressive stress are functions of compressive strain, a relation between compressive stress and normalized cumulative AE hits was calculated when the compressive strain was available. By suggested procedures, it was possible to monitor pretested plain or random distributed short fibers reinforced adobe elements (with AE sensor and strain detector) in a masonry building under uniaxial compression loading to predict the situation of element in the compressive stress‒strain curve, hence predicting the time to element collapse by an AE sensor and a strain detector. In the predicted compressive stress‒strain curve, the peak stress and its corresponding strain, the stress and strain point with maximum elastic modulus and the maximum elastic modulus were predicted successfully. With a proposed material model, it was illustrated that the needed parameters for simulating a specimen in Abaqus software with concrete damage plasticity were peak stress and its corresponding strain, the stress and strain point with maximum elastic modulus and the maximum elastic modulus. Findings The AE cumulative hits versus strain plots corresponding to the stress‒strain curves can be divided into four stages: inactivity period, discontinuous growth period, continuous growth period and constant period, which can predict the densifying, linear, non-linear and residual stress part of the stress‒strain relationship. By supposing that the relation between cumulative AE hits and compressive strain complies with a Weibull distribution function, a linear analysis was conducted to calibrate the parameters of Weibull distribution by AE cumulative hits for predicting the failure probability as a function of compressive strain. Parameters of m and θ were able to predict the brittleness of the plain and tire fibers reinforced adobe elements successfully. The calibrated failure probability function showed sufficient representation of the cumulative AE hit curve. A mathematical model for the stress–strain relationship prediction of the specimens after detecting the first AE hit was developed by the relationship between compressive stress versus the Weibull failure probability function, which was validated against the experimental data and gave good predictions for both plain and short fibers reinforced adobe specimens. Then, the authors were able to monitor and predict the situation of an element in the compressive stress‒strain curve, hence predicting the time to its collapse for pretested plain or random distributed short fibers reinforced adobe (with AE sensor and strain detector) in a masonry building under uniaxial compression loading by an AE sensor and a strain detector. The proposed model was successfully able to predict the main mechanical properties of different adobe specimens which are necessary for material modeling with concrete damage plasticity in Abaqus. These properties include peak compressive strength and its corresponding axial strain, the compressive strength and its corresponding axial strain at the point with maximum compressive Young’s modulus and the maximum compressive Young’s modulus. Research limitations/implications The authors were not able to decide about the effects of the specimens’ shape, as only cubic specimens were chosen; by testing different shape and different size specimens, the authors would be able to generalize the results. Practical implications The paper includes implications for monitoring techniques and predicting the time to the collapse of pretested elements (with AE sensor and strain detector) in a masonry structure. Originality/value This paper proposes a new method to monitor and predict the situation of a loaded element in the compressive stress‒strain curve, hence predicting the time to its collapse for pretested plain or random distributed short fibers reinforced adobe (with AE sensor and strain detector) in a masonry building under uniaxial compression load by an AE sensor and a strain detector.

Densification process aims to improve the physical and mechanical properties of wood and bamboo products. However, its processing parameters were not yet thoroughly investigated for bamboo. In this study, Dendrocalamus asper bamboo was densified in its radial direction in an open thermal press with different starting moisture content (MC), from 0 to 20%, to evaluate its effect on bending and physical-chemical properties. A maximum densification degree of 31.2% was achieved. Physical characterization and three-point bending tests showed that densification process increases density and all related bending properties (modulus of rupture (MOR), modulus of elasticity (MOE), the limit of proportionality (LOP), and specific energy (SE)) of bamboo, producing a more homogeneous material. The densified samples with 10% MC presented the best bending properties, with an average MOR, MOE and dynamic MOE of 318, 27,754 and 34,120 MPa respectively, with an increase of 56% for MOR and 41% for MOE in comparison with un-densified samples. SEM analysis of fractured samples showed an improvement of the fibers-parenchyma interface after thermo-mechanical modification, confirmed by the presence of unitary fiber failure. XRD analysis revealed that although densified bamboo had higher cellulose crystallinity compared to un-densified samples, the starting moisture content did not affect on the cellulose structure. FTIR showed that there are no significant changes in the chemical composition in all the analyzed conditions. However, the samples with moisture content below 5% presented cracks during the thermal-mechanical process, which resulted in higher thickness swelling and water absorption. Additionally, when samples with 20% MC are densified, an excess of water entrapped in the middle of the samples causes heterogeneous densification. The control of the initial moisture content of bamboo is a strategic parameter to improve the efficiency of the densification process. An initial moisture content around 10% is recommended for bamboo, which can guarantee enough plasticization and at the same time homogeneous properties in the final product. (C) 2019 Elsevier Ltd. All rights reserved.

Since the 70ties local energy saving materials, cement composites reinforced with vegetable fibers, bamboo as well as renovated ancient technologies started to be investigated by scientists and researchers in order to substitute industrialized materials which are highly polluting and high energy demanding in their production. Although proved technically and scientifically that the newly developed non-conventional materials and technologies (NOCMAT) were superior to the conventional industrialized materials they have not been used in large-scale projects. There is an intense on-going search in Brazil for non-polluting materials which consume little energy in their production and/or utilization. Even with the accumulation of technical data concerning the developed materials and structural elements obtained from the research programs, they are not systematically used in large scale in civil construction. Therefore, a systematic and methodological evaluation framework is needed. In this paper a short description of the materials and structural elements using bamboo are given. Then the evaluation tools for the successful implementation of the results in large NOCMAT projects is discussed considering those Research and Development (R&D) projects sponsored by Redebambu/BR the recent network created in Brazil, which applies the national policy to encourage the bamboo's handling and sustainable planting. Five important outcomes reflected into the NOCMAT R&D projects such as Efficiency, Effectiveness, Impact, Relevance and Sustainability and its pertinent indicators are presented. Additionally, four relevant dimensions, specifically, (1) Political, Strategic and Normative; (2) Organizational; (3) Allocation and Management of Resources; and (4) Technical, Scientific and Economic evaluation dimensions are considered and discussed.