Alkaline degradation of wood: Effects on Young's modulus

Tamburini, Umberto Anselmi

doi:10.1007/bf00386404

Cited by 9 publications

(4 citation statements)

References 6 publications

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“…On the other hand, cement, i.e. the alkaline milieu, has a negative influence on the mechanical and dimensional properties of wood by chemical degradation of the wooden components, as explained by Tamburini (1970), Mašura (1982), Fan et al (1999), and Knill and Kennedy (2003). Chemical degradation is also visually evident by discolouration in the wood due to the water-soluble phenolic components (Hon and Shiraishi 2001;Frybort et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Mechanical Interactions at the Interface of Wood-Cement Composites by Means of Electronic Speckle Pattern Interferometry

Frybort¹,

Mauritz²,

Teischinger³

et al. 2012

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This study investigates the bonding behaviour of Norway spruce wood strands to a surrounding cement matrix. Effects of wood swelling and shrinking during cement curing were studied by using strands of various thicknesses. The deformation of the spruce wood strands and the surrounding cement matrix, as well as the interface between the wood and the cement were examined using Electronic Laser Speckle Interferometry (ESPI) while applying a pull-out load. Sample deformation was transformed to shear strain maps, showing which side of the strand was tightly bonded to the cement matrix. The analysis of the strain maps proved that all strands were tightly bonded to the cement matrix on only one side. No shear deformation was observed on the loosely bonded side, meaning that there was no adhesion on that side between the wood strand and the cement matrix. Manufacturing of strands results in different surface characteristics and surface roughness. Bringing together the ESPI results with the roughness measurements, it was shown that only the comparably rougher surface adheres to the cement matrix. In a cement bonded composite (CBC) made of lignocellulosics to a greater or lesser extent, only half of the contact area is therefore able to transfer load.

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Section: Introductionmentioning

confidence: 99%

Investigation of the Mechanical Interactions at the Interface of Wood-Cement Composites by Means of Electronic Speckle Pattern Interferometry

Frybort¹,

Mauritz²,

Teischinger³

et al. 2012

BioResources

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“…The design methods of an RSW consider a rigid bond between steel reinforcement and grout, as the connection between soil and grout is the weakest link within the nail -cementsoil system in general. Published results of concrete-reinforcement pull-out tests (Ritter 2013;Simons 2007) reveal a pull-out strength between reinforcement tendon and concrete by at least a decimal power higher compared to the results presented in Fig. 13.…”

Section: Characteristic Shear Force For Soil Nailing Designmentioning

confidence: 63%

Wood-cement-composite behaviour of beech circular hollow sections

et al. 2020

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Beech laminated veneer lumber (LVL) circular hollow sections for use as nails in temporary geotechnical soil nailing systems were developed within this research. For the soil wall stability, beside a sufficient load carrying capacity of the nail cross section, a load carrying connection between the cement annulus and the nail is necessary. As cement grout ensures the bond between the nails and soil for the mobilisation of a soil reinforcement effect, a reliable connection between cement and wood surface is required. Occurring shear forces must be transferred from the nail into the soil through the wood-cement interface similar to reinforced concrete. Pull-off tests on clear LVL specimens with different cement and wood surface modifications as well as the results of large-scale push-out tests are presented. The results reveal a sufficient short-term bonding strength between the cement annulus and the wooden member to transfer the geotechnical loads, but also highlight the necessity of further research on long-term behaviour.

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“…Mechanical tests of chemically delignified pine, beech, and poplar wood and of single pine-wood fibres have shown that there is a pronounced decrease of wood strength in comparison to native wood when tested in a wet state (Klauditz, 1952); in a dry state, the strength is either unchanged or even increased for the delignified wood and the fibres. Tamburini (1970) mechanically tested alkaline-treated beech wood with partially removed lignin and hemicelluloses in a dry state and obtained similar patterns for wood stiffness and strength. In addition, Zhang et al (2013) performed single-fibre tests on delignified Chinese fir wood in a dry state and did not find any decreases in stiffness and strength.…”

Section: Introductionmentioning

confidence: 82%

Significant influence of lignin on axial elastic modulus of poplar wood at low microfibril angles under wet conditions

Özparpucu

Gierlinger

Cesarino

et al. 2019

Journal of Experimental Botany

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Wood is extensively used as a construction material. Despite increasing knowledge of its mechanical properties, the contribution of the cell-wall matrix polymers to wood mechanics is still not well understood. Previous studies have shown that axial stiffness correlates with lignin content only for cellulose microfibril angles larger than around 20°, while no influence is found for smaller angles. Here, by analysing the wood of poplar with reduced lignin content due to down-regulation of CAFFEOYL SHIKIMATE ESTERASE, we show that lignin content also influences axial stiffness at smaller angles. Micro-tensile tests of the xylem revealed that axial stiffness was strongly reduced in the low-lignin transgenic lines. Strikingly, microfibril angles were around 15° for both wild-type and transgenic poplars, suggesting that cellulose orientation is not responsible for the observed changes in mechanical behavior. Multiple linear regression analysis showed that the decrease in stiffness was almost completely related to the variation in both density and lignin content. We suggest that the influence of lignin content on axial stiffness may gradually increase as a function of the microfibril angle. Our results may help in building up comprehensive models of the cell wall that can unravel the individual roles of the matrix polymers.

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Alkaline degradation of wood: Effects on Young's modulus

Cited by 9 publications

References 6 publications

Investigation of the Mechanical Interactions at the Interface of Wood-Cement Composites by Means of Electronic Speckle Pattern Interferometry

Investigation of the Mechanical Interactions at the Interface of Wood-Cement Composites by Means of Electronic Speckle Pattern Interferometry

Wood-cement-composite behaviour of beech circular hollow sections

Significant influence of lignin on axial elastic modulus of poplar wood at low microfibril angles under wet conditions

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