When field seam test results sail, yet laboratory test results pass: A practical approach to understanding why

¹ AGRU America
² Chesapeake Containment System, Inc.
³ Geosynthetic Institute (GSI)

^* Corresponding author: gsigeokoerner@gmail.com

Abstract

A standard quality control (QC) and quality assurance (QA) plan during installation of an unreinforced polyethylene geomembrane often requires destructive testing of the production welded seams at regular intervals. This testing is different from “trial weld testing.” Prior to welding of the seams, within the project footprint, a “trial weld” is fabricated on site as a proficiency test. The procedure utilizes project specific geomembrane material, environmental conditions, welding technician and equipment intended to perform the seaming of geomembrane installed as part of the containment system. There are cases where on-site trial welds become difficult to pass, even when experienced crews, quality equipment and materials are present. The difficulty can lead to a scenario where trial welds fail and destructive seam tests pass when sent to a 3rd party lab for testing, (this is a nightmare for geomembrane installers). Variables are numerous and often difficult to identify between these two different testing scenarios. However, this paper will show results and insightful data that will give rationale for the discrepancy.