Laboratory Survivability of Nonwoven Geotextiles on Open-Graded Crushed Aggregate

Abstract

A laboratory method of assessing survivability of a nonwoven geotextile laid on open-graded crushed aggregate was developed. Preliminary suggestions for the application to compaction forces and/or traffic forces are given. Phase 1 involved compaction using a modified California Bearing Ratio (CBR) test with a geotextile sandwiched between two soil layers. Phase 2 involved tension testing of the damaged geotextile. In order to undertake Phase 2, a 200 mm wide-width strip tensile test methodology that did not use grips was developed and is presented. The test variables examined in the CBR phase of the testing were the particle size of the cover material, the mass of the geotextile, and the compaction energy of the CBR tests (via the ram mass and drop height). The particle size of the bedding material and the thickness of both the cover and bedding material were kept constant. The results, in terms of damage to the geotextile, show: (i) the smaller the compaction energy the less geotextile damage; (ii) the greater the mass per unit area, or thickness, of the geotextile the less geotextile damage; and (iii) the smaller the particle size of the aggregate overlying the geotextile the less geotextile damage. This last result was very evident when the particle size was < 2 mm. The tensile testing technique used a geotextile loop joined with a rapidly applied hot glue that permitted immediate testing. The loop technique also avoided the lateral restraining effect of full-width grips.