An Assessment of Current GCL Manufacturing Quality Control and On-Site Acceptance Testing Standard of Practice

Abstract

The intent of establishing an ASTM standard practice for geosynthetic clay liner (GCL) manufacturing quality control (MQC) (ASTM D 5889) and a guide for construction quality assurance (CQA) (ASTM D 6495) acceptance testing requirements is to lead the industry toward a common standpoint with regard to GCL material requirements and testing. Although these methods provide the design practitioner a baseline for specifying GCL material properties and testing, the acceptance of these methods by the design community is dependent upon the intent of each design, the differences in GCL materials and the designer's exposure to GCLs. An assessment of GCL material properties and testing outlined in the ASTM methods for MQC and CQA testing is presented. To gage the extent to which the methods have standardized the North American GCL market, the authors compare the ASTM methods to 160 GCL specifications from projects they were involved over the past year. Although approximately 70 % of the actual GCL project specifications conform to the current industry standard of practice, additional progress in promoting the ASTM methods and test designations will further standardize MQC and CQA testing whereby reducing exceptions and clarifications between GCL manufacturers and designers. From this comparison, the authors present recommended changes to the current ASTM MQC and CQA standards to bring the ASTM standards in line with current state of the practice GCL testing.