Special Issue "Bio-composite Materials and Structures"

Submission Deadline: 31 December 2019 (closed)
Guest Editors
Haitao Li, Professor, Nanjing Forestry University

Summary

This Special Issue is mainly about the green building materials and structures, such as timber, bamboo, straw and other biomass materials and structures and so on. Papers about the test methods, mechanical properties and structural applications for sustainable materials and structures are welcome.


Keywords
Bamboo; Wood; Timber; CLT; Straw; bio-composite materials and structures; Strain; Stress; Strength; Modulus; Deflection; Stiffness; Ductility; Tensile;Compression; Shear; Bending; Bricks; Beam; Column; Joint; Frame

Published Papers
  • Improving the Antibacterial Property of Chitosan Hydrogel Wound Dressing with Licorice Polysaccharide
  • Abstract A series of hydrogels with different ratios of chitosan and licorice polysaccharide (LP) were prepared by crosslinking to different concentrations of genipin (gp). They were characterized by FTIR (Fourier transform infrared spectroscopy), SEM (Scanning electron microscope), swelling ratio, rheological measurements, degradation with time, cytotoxicity, and antibacterial efficacy. Results show that the hydrogels have porous structures. With an increase in LP content, the swelling rate grows in the early stage of immersion in buffer and drops later. The swelling ratio ranged from 986% to 1677%, and stiffness varied from 777 Pa to 1792 Pa. The addition of LP reduced the mechanical… More
  •   Views:169       Downloads:161        Download PDF

  • Mechanical Characterisation of Densified Hardwood with Regard to Structural Applications
  • Abstract The demand for high-performance, yet eco-friendly materials is increasing on all scales from small applications in the car industry, instrument or furniture manufacturing to greater dimensions like floorings, balcony furnishings and even construction. Wood offers a good choice on all of these scales and can be modified and improved in many different ways. In this study, two common European hardwood species, Beech (Fagus sylvatica L.) and Ash (Fraxinus excelsior L.) were densified in radial direction by thermo-mechanical treatment and the densified product was investigated in an extensive characterisation series to determine all relevant mechanical properties. Compression in the three main… More
  •   Views:473       Downloads:332        Download PDF

  • Mechanical Behavior of Light Trusses Made of Poplar Laminated Veneer Lumber and Connected with Bolts and Tooth Plates
  • Abstract Poplar Laminated Veneer Lumber (Poplar LVL) is a new type of engineering materials with high strength, good reliability and small variability. Poplar LVL is manufactured from the fast-growing poplar, which is widely used in packaging, furniture and others, however, is rarely adopted in construction. In order to explore the feasibility of poplar LVL trusses in construction of roof, four 4.5-m-span Fink-and-Howe trusses were designed and assembled, which were made of poplar LVL with bolted- and tooth-plated connections. Vertical static loading on the upper chord joints of a truss was imposed by self-balancing test device. The mechanical properties of trusses were… More
  •   Views:311       Downloads:251        Download PDF

  • On Designing Biopolymer-Bound Soil Composites (BSC) for Peak Compressive Strength
  • Abstract Biopolymer-bound Soil Composites (BSC), are a novel bio-based construction material class, produced through the mixture and desiccation of biopolymers with inorganic aggregates with applications in soil stabilization, brick creation and in situ construction on Earth and space. This paper introduces a mixture design methodology to produce maximum strength for a given soil-biopolymer combination. Twenty protein and sand mix designs were investigated, with varying amounts of biopolymer solution and compaction regimes during manufacture. The ultimate compressive strength, density, and shrinkage of BSC samples are reported. It is observed that the compressive strength of BSC materials increases proportional to tighter particle packing… More
  •   Views:440       Downloads:362        Download PDF

  • Axial Mechanical Properties of Timber Columns Subjected to Freeze-Thaw Cycles
  • Abstract The behaviour of timber columns subjected to freeze-thaw cycles under axial compression is presented in this paper. A total of forty specimens, including twenty circular timber columns and twenty square timber columns, were tested under axial compression. The failure modes, ultimate bearing capacity, ductility coefficient, load-displacement curves and load-strain curves were obtained and analyzed. The number of freeze-thaw cycles (from 0 to 80) and the specimens’ height (from 225 mm to 360 mm) were considered as the main parameters. After freeze-thaw cycles, there was no obvious change on the surface of the timber columns. The test results showed that freeze-thaw… More
  •   Views:445       Downloads:360        Download PDF

  • Experimental and Theoretical Study on Bonding Properties between Steel Bar and Bamboo Scrimber
  • Abstract To further verify the feasibility of newly designed reinforced bamboo scrimber composite (RBSC) beams used in building construction, the bonding properties between steel bar and bamboo scrimber were investigated by anti-pulling tests. Results indicated that the anti-pulling mechanical properties were signifi- cantly correlated to the diameter, thread form and buried depth of steel bar, forming density of bamboo scrimber as well as the heat treatment of bamboo bundle. There were two failure modes for anti-pulling tests: the tensile fracture and pulling out of steel bar. Both the ultimate load and average shear strength of anti-pulling specimen could be increased greatly… More
  •   Views:1011       Downloads:616        Download PDF

  • Bond Performance of Adhesively Bonding Interface of Steel-Bamboo Composite Structure
  • Abstract The steel-bamboo composite structure is a newly developed structure, combining phyllostachys pubescens (also called Moso bamboo) plywood and cold-formed thin-walled steel with structural adhesive. The reliability of steelbamboo interface is the premise of composite effect. 13 specimens were prepared to investigate the failure modes and mechanism of the steel-bamboo interface on the basis of push-out test, and the strain difference analysis method was proposed to study the distribution of shear stress. The results show that the main failure modes of steel-bamboo interface are adhesion failure and splitting of bamboo plywood. The shear stress is not evenly distributed along the longitudinal… More
  •   Views:983       Downloads:519        Download PDF

  • Strength Degradation of Wood Members Based on the Correlation of Natural and Accelerated Decay Experiments
  • Abstract An accelerated decay test and a natural decay test were conducted synchronically to explore the strength degradation of decaying wood members under long-term exposure to natural environment. A natural decay test was carried out to measure the bending strength, compressive strength parallel to grain and modulus of elasticity of the wood members, with 6 groups of specimens decayed in natural environment for 3 to 18 months respectively. To compare with corresponding decay test, in which 6 other groups of specimens were measured under accelerated conditions. The experimental data collected were evaluated by Pearson productmoment for the correlation. The results indicate… More
  •   Views:866       Downloads:356        Download PDF

  • Experimental Study on the Creep Behavior of Recombinant Bamboo
  • Abstract The creep behavior of bamboo due to the complicated influences of environment and stress will lead to a sustained increase in deformation, which serious effects the service performance of structures. To investigate the creep behavior of recombinant bamboo, twenty-four recombinant bamboo specimens were tested under lasting compressive and tensile loads at different load levels. The typical failure modes of recombinant bamboo under a lasting load at a high load level were buckling failure and brittle fracturing due to creep compressive creep and tensile creep development, respectively. At a high load level, the creep deformation of recombinant bamboo initially develops unsteadily… More
  •   Views:521       Downloads:401        Download PDF

  • Experimental Research on Structural Behaviors of Glulam I-Beam with a Special-Shaped Section
  • Abstract In order to enhance the bearing capacity of structural components, save materials, and reduce cost, a glued laminated timber (glulam) I-beam that is theoretically suitable for engineering application was proposed. In this study, 18 glulam specimens were fabricated using larch dimension lumber and resorcinol– formaldehyde resin. Four-point bending tests were carried out to compare the ultimate bearing capacity, strain, and deflection of various specimens. The results showed that: (1) The typical failure mode at bending is the web shear failure parallel to grain. Before the failure, cracks and sounds appear at the beam web, which represent the sudden brittle failure.… More
  •   Views:1959       Downloads:604        Download PDF

  • Compression Behaviors of Parallel Bamboo Strand Lumber Under Static Loading
  • Abstract In order to investigate the influence of length and compression directions upon behaviour of parallel bamboo strand lumber (PBSL) specimens, 240 axial compression tests have been performed. With three similar one different typical failure modes, the mechanical performance for PBSL specimens under compression parallel to grain and perpendicular to grain are different as a whole. From the point of the characteristic values, the compression strength parallel to grain is 2.1 times of the compression strength perpendicular to grain. The elastic modulus for compression parallel to grain is 3.64 times of the compression strength perpendicular to grain. While the compression ratios… More
  •   Views:1253       Downloads:675        Download PDF

  • Evaluation of Mechanical Properties of Cross-Laminated Timber with Different Lay-ups Using Japanese Larch
  • Abstract Japanese larch is one of the main plantation tree species in China. A lack of engineered wood products made by Japanese larch , limits its application in wood structures. In this study, based on optimum process para meters, such as pressure (1.2 MPa), adhesive spread rate (200 g/m 2 ) and adhesive (one component polyurethane), the mechanical properties of Japanese larch made cross laminated timber ( with different lay ups were evaluated by means of the static method . Results of this study show ed that variations in lay ups significant ly affected the mechanical properties of CLT. The strength… More
  •   Views:2870       Downloads:499        Download PDF

  • Thermal Responses of Woods Exposed to High Temperatures Considering Apparent Thermo-Physical Properties
  • Abstract It is well known that the use of woods as construction materials can embody carbon content of structural members, which can enhance the urban sustainability. However, due to the combustibility of wood, its current application is restricted. To broaden the application of wood, its thermal responses exposed to fire (high temperature) is investigated in this study. Firstly, the wood kinetic parameters are determined by coats-redfern method using thermal gravimetric (TGA) data. Secondly, the density and thermal conductivity are obtained from parallel and series models. Thirdly, the specific heat capacity formula is presented considering latent and decomposition heat, which can be… More
  •   Views:1833       Downloads:455        Download PDF

  • Mechanical Properties of a Eucalyptus-Based Oriented Oblique Strand Lumber for Structural Applications
  • Abstract Wood and wood-based composite materials have gained increasing attention in the sustainable building industry because of their renewability and environmental friendliness. Oriented oblique strand lumber (Eucalyptus Strand Wood, ESWood), which is manufactured from fast-growing small diameter eucalyptus wood (Eucalyptus urophylla × E. grandis), is introduced in this paper. Small clear specimen tests were conducted to determine the mechanical properties of ESWood material while full-scale component tests were performed to observe the structural performance of ESWood beams. A comparison of mechanical properties of ESWood with other wood/bamboo-based materials is then reported. From the results presented herein, it appears that the strength… More
  •   Views:1307       Downloads:515        Download PDF

  • Study on Thermal Insulation Performance of Cross-Laminated Bamboo Wall
  • Abstract In recent years, bamboo, as a green building material, has attracted more and more attention worldwide. Inspired by the investigation of cross-laminated timber in structural systems, a new engineered cross-laminated bamboo (CLB) consisting of the cross lamination of bamboo scrimber plates is proposed in this paper. To evaluate its potential in structural applications, the thermal insulation performances of the CLB walls and CLB walls with the EPS foam plate were studied and evaluated by the temperature-controlled box-heat flow meter method. Test results indicated that the thermal insulation performance improved with the increase of thickness, but different wall configurations had little… More
  •   Views:2097       Downloads:481        Download PDF

  • Flexural Performance of CFRP-Bamboo Scrimber Composite Beams
  • Abstract This study presents a new structure made up of bamboo scrimber and carbon fiber reinforced polymer (CFRP) to address the low stiffness and strength of bamboo scrimbers. Three-point bending test and finite element model were conducted to study the failure mode, strain-displacement relationship, load-displacement relationship and relationships between strain distribution, contact pressure and deflection, and adhesive debonding. The results indicated that the flexural modulus and static flexural strength of the composite beams were effectively increased thanks to the CFRP sheets. The flexural modulus of the composite specimens were 2.33-2.94 times that of bamboo scrimber beams, and the flexural strength were… More
  •   Views:637       Downloads:569        Download PDF

  • Evaluation of the Out-of-Plane Shear Properties of Cross-Laminated Timber
  • Abstract The out-of-plane shear properties of cross-laminated timber (CLT) substantially influence the overall mechanical properties of CLT. Various testing methods and theories related to these properties have recently been developed. The effects of the number of layers (three and five layers) and testing method (short-span three- and four-point bending tests) on the out-of-plane shear properties of CLT were evaluated. The out-of-plane shear strength values were calculated based on different theories for comparison. The failure mode in the short-span four-point bending (FPB) method was mainly the rolling shear (RS) failure in the cross layers, indicating that the FPB method was appropriate to… More
  •   Views:1984       Downloads:548        Download PDF