Characteristic pore size of nonwoven geotextiles based on low-field nuclear magnetic resonance technology

Abstract

Conventional methods for assessing the pore characteristics of nonwoven geotextiles are plagued by several limitations such as low accuracy and lengthy processing time. Consequently, this paper proposed low-field nuclear magnetic resonance (NMR) technology to acquire the pore size distribution (PSD) curves, porosity, and characteristic pore size (CPS) of nonwoven geotextiles. The T2 characteristic spectrum of vacuum-saturated specimens was obtained from low-field NMR tests, while the pore shape coefficient and surface relaxation rates were determined via scanning electron microscopy (SEM) and X-ray computed tomography (CT) three-dimensional (3D) reconstruction technology. The PSD curves and CPS (O90) values were acquired and compared with results from the wet sieving, dry sieving, and CT digital image methods. The results demonstrate that low-field NMR technology can accurately and efficiently determine the CPS of nonwoven geotextiles.