Prediction of Pore Size Characteristics of Needle‐Punched Nonwoven Geotextiles Subjected to Uniaxial Tensile Strains

Abstract

A modified theoretical model has been proposed to predict the pore size characteristics of nonwoven geotextiles under certain uniaxial tensile strains, considering the difference between the out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles. The pore size distributions (PSDs) and O95 subjected to different levels of uniaxial tensile strains in two needle-punched nonwoven geotextiles have been investigated by the dry sieving test. The variation of the fibre orientation with tensile strains and the corresponding effect on pore sizes has been evaluated by image analysis. The out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles have been examined. A comparison has been made between the predictions of the original and the modified models. It is shown that the modified model can more accurately predict the decreasing rate of the PSDs, O95, and O98 than the original one. The corrected theoretical O95 and O98 under certain strains can provide a reference for the filtration design under engineering strains. The fibres reorientating to the loading direction result in the increase of the directional parameter with increasing tensile strains, which leads to the decrease of pore sizes. The theoretical PSDs are sensitive to the variation of directional parameter.

Towards Multi-Angle Multispectral Optical 3D Porometry and Lens-Less Porometry of Civil Engineering Composites and Geocomposites Including Biodegradable Ones

“…Pore measurements can be used not only for solidified construction composites, but also for their precursors (such as mineral aggregates and nodules -from clays and lime to sand) [12,13]. For polymer composite materials in real construction building environmental conditions (such as soil, atmospheric and hydrospheric media for geopolymers [14] and geotextiles [15][16][17][18]), porosimetry or porometry is a very important element of the protocols of their physical characterization for hygroscopicity and percolation testing. It is possible to consider two concurrent trends in application of fiber geocomposites and geotextiles for the above mentioned purposes.…”