Manufacturing Quality Control and Specification Criteria for Geosynthetic Clay Liners

Abstract

Geosynthetic clay liner (GCLs) combine geological materials with synthetic fabrics and require a new approach to conformance and quality control testing. GCLs have been used in various sealing applications over the last 10 years and have found an increased use in landfill applications. Therefore during the June 1993 ASTM meetings, a GCL subcommittee, D 35.04 was created with Mr. Larry Well of CH2M Hill, Portland, OR. serving as subcommittee chairman. The subcommittee comprises 6 task groups: • Physical properties • Manufacturing quality control and assurance (MQC/MQA), • Logistics, • Endurance, • Hydraulic properties, and • Mechanical properties. As an example, the Manufacturing QC/QA task group has currently developed a standard of practice for manufacturing quality control of GCLs, and methods for determining a swell index value for clay and the fluid loss of the clays. A standard for manufacturing quality assurance is currently in development. In the past quality control and quality assurance programs were developed by various manufacturers resulting in QC/QA programs which benefit the manufacturers products and not necessarily the project requirements. Another problem is the fact that the construction quality control and quality assurance (CQC/CQA) plan is often written in isolation by different people from those writing the MQC plan [1]. This paper will discuss the state-of-the-art of quality control and quality assurance for GCL testing to help to maximize GCL performance.