Journal Article

3D fibre architecture of fibre-reinforced sand

Diambra, A., Laurencin, T., Moro, P., Viggiani, G., Soriano, I., Andò, E., Ibraim, E.

2017

Overview

The mechanical behaviour of fibre-reinforced sands is primarily governed by the three-dimensional fibre architecture within the sand matrix. In laboratory, the normal procedures for sample preparation of fibre-sand mixtures generally produce a distribution of fibre orientations with a preferential bedding orientation, generating strength anisotropy of the composite’s response under loading. While demonstrating the potential application of X-ray tomography to the analysis of fibre-reinforced soils, this paper provides for the first time a direct experimental description of the three-dimensional architecture of the fibres induced by the laboratory sample fabrication method. Miniature fibre reinforced sand samples were produced using two widely used laboratory sample fabrication techniques: the moist tamping and the moist vibration. It is shown that both laboratory fabrication methods create anisotropic fibre orientation with preferential sub-horizontal directions. The fibre orientation distribution does not seem to be affected by the concentration of fibres, at least for the fibre concentrations considered in this study and, for both fabrication methods, the fibre orientation distribution appears to be axisymmetric with respect to the vertical axis of the sample. The X-ray analysis also demonstrates the presence of an increased porosity in the fibre vicinity, which confirms the assumption of the “stolen void ratio” effect adopted in previous constitutive modelling. A fibre orientation distribution function is tested and a combined experimental and analytical method for fibre orientation determination is further validated.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V,Springer Verlag
• Subject: Architecture / Complex Fluids and Microfluidics / Condensed Matter / Distribution functions / Engineering Fluid Dynamics / Engineering Sciences / Engineering Thermodynamics / Fiber orientation / Fiber reinforced materials / Foundations / Geoengineering / Heat and Mass Transfer / Horizontal orientation / Hydraulics / Industrial Chemistry/Chemical Engineering / Laboratories / Materials / Materials Science / Mechanical properties / Mechanics / Mechanics of materials / Original Paper / Physics / Physics and Astronomy / Reinforced soils / Sand / Soft and Granular Matter / Soil analysis / Soil porosity / Solid mechanics / Statistical Mechanics / Tamping / Void ratio / X ray analysis