Thesis Details

Thesis Title: Establishing an alternative index test method for testing the tensile strength of nonwoven geotextiles
Thesis Author: Mark Mezger
Abstract: The nonwoven industry has experienced significant growth over the past 25 years. As of 1992, approximately 17.2 billion square yards of nonwoven fabrics had been consumed. Nonwovens hold the largest share of the geotextile market over knit and woven fabrics, and the most commonly fiber utilized in this industry is polypropylene. The most common form of nonwoven geotextiles are produced by needlepunching fibers together and then thermally bonding the web. A needlepunched nonwoven fabric primarily achieves its strength through fiber entanglement and fiber-to-fiber friction. The inherent loose construction of a needlepunched nonwoven can become compact under compression, increasing the fiber-to-fiber contact, with increased fiberto- fiber friction, compressed geotextiles exhibit different physical properties than non- I confined geotextiles. The purpose of this thesis was to develop an index test method for evaluating nonwoven geotextiles under compressed conditions. A total of 216 conditions were utilized to determine the "best" set-up for testing nonwoven geotextiles under confined conditions. Sample shape, compressive force, compressive plate covers, and fabric style were evaluated during the optimization. Following the optimization process, a total of 24 fabric conditions were produced to determine if certain levels of fabric properties are detectable under confined conditions. The fabrics produced had various levels of needlepunch density, fiber tenacity, calendering, and fabric weight. The results indicated that the confined tensile test produced significantly higher tensile strengths than the standard grab test. The trends of various fabric properties could be clearly seen and were more apparent when utilizing the confined tensile test.