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We report on the design and realization of an x-ray imaging system for quantitative phase-contrast microscopy at high x-ray energy with laboratory-scale instrumentation. Phase and amplitude were separated quantitatively at x-ray energies up to 80 keV with micrometric spatial resolution. The accuracy of the results was tested against numerical simulations, and the spatial resolution was experimentally quantified by measuring a Siemens star phase object. This simple setup should find broad application in those areas of x-ray imaging where high energy and spatial resolution are simultaneously required and in those difficult cases where the sample contains materials with similar x-ray absorption.

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 along two compression directions are equal to each other. The bigger Poisson ratios for one typical side surface is 3.93 times of that for another typical side surface for PBSL specimens under compression perpendicular to grain, and the bigger value is equal to that for PBSL specimens under compression parallel to grain. Length can influence the mechanical properties of the PBSL specimens. The size 50 mm × 50 mm × 100 mm should be good choice for the standard or code to measure the compression strength. PBSL materials have better ductility under compression parallel to grain than that under compression perpendicular to grain. Stress-strain relationship models were proposed for PBSL specimens under compression parallel to grain and perpendicular to grain, respectively. These proposed models gave a good agreement with the test results.

The large-scale urbanisation taking place in the developing world requires the construction industry to adopt alternative non-conventional renewable materials to reduce the unsustainable level of greenhouse gas emissions associated with the production of industrialised building materials. Bamboo is one of the most promising non-conventional building materials endemic to most developing countries, but there is still insufficient consistent information on the physical and mechanical properties of the numerous species suitable for construction. This study shows the potential of robotic fabrication to accelerate testing programmes on small clear samples of bamboo required to compare physical and mechanical properties across different species and differing plantation management practices. This fabrication method is applied on an experimental testing programme to determine the characteristic values of density, compressive strength, elastic modulus and shear strength of Phyllostachys pubescens (moso), Guadua angustifolia Kunth (guadua) and Guadua angustifolia (oldhamii). The efficient development of comprehensive experimental datasets of clear samples of bamboo is fundamental to inform the development of future design guidelines for bamboo as a construction material.

Bamboo is a green construction material in line with sustainable development strategies. The use of raw bamboo in architecture has existed since ancient times. In the long development years of original bamboo buildings, many areas in the world gradually formed unique bamboo buildings, which have become an important local cultural feature. For building structures, joints are the key to ensure structural load transfer. Because of hollow and thin-walled material property of bamboo, the connection in raw bamboo buildings has always been a major difficulty and problem in the application of bamboo, which seriously hinders the development of original bamboo structures. In order to promote the use of raw bamboo, two traditional connection methods in raw bamboo structures are described in this paper firstly, with the advantages and disadvantages of the two methods pointed out. Also, research progress on four categories of raw bamboo building joints is described namely, bolt joints, steel member joints, filler reinforced joints and other types of joints. This work can provide a reference for future research and engineering applications.

In order to investigate the basic mechanical properties and stress strain relationship model for bamboo scrimber manufactured based on a new technique, a large quantities of experiments have been carried out. Based on the analysis of the test results, the following conclusions can be drawn. Two main typical failure modes were classified for bamboo scrimber specimens both under tension parallel to grain and tension perpendicular to grain. Brittle failure happened for all tensile tests. The slope values for the elastic stages have bigger discreteness compared with those for the specimens under tensile parallel to grain. The failure modes for bamboo scrimber specimens under compression parallel to grain could be divided into four. Only one main failure mode happened both for the bending specimens and the shear specimens. With the COV values of 28.64 and 25.72 respectively, the values for the strength and elastic modulus under tensile perpendicular to grain have the largest discreteness for bamboo scrimber. From the point of CHV values, the relationship among the mechanical parameters for bamboo scrimber were proposed based on the test results. Compared with other green building materials, bamboo scrimber manufactured based on a new technique has better mechanical performance and could be used in construction area. Three stress strain relationship models which are four-linear model, quadratic function model, and cubic function model were proposed for bamboo scrimber specimens manufactured based on a new technique. The latter two models gives better prediction for stress strain relationship in elastic plastic stage.

Slenderness ratio is one of the main influencing factors on the mechanical properties of LBL column under eccentric compression. This paper presents the research results of 20 column tests. Two main failure models can be classified based on the test results for the LBL columns. The increasing speeds for the strain value are similar for all specimens. Regardless of the length, the strain across the cross-section of the LBL column for each specimen is basically linear throughout the loading process, following standard normal section bending theory. The relationships between the ultimate mechanical parameters and slenderness ratios were proposed, including an equation for calculating slenderness ratio influencing coefficient λ  which gives a good agreement with the test results. All the equations presented in this paper can be used as reference for further work to establish a generally applicable formula for code adoption.

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