JOURNAL ARTICLES

PLASTICIZER MOLECULAR WEIGHT AND PLASTICIZER RETENTION IN PVC GEOMEMBRANES PLASTICIZER MOLECULAR WEIGHT AND PLASTICIZER RETENTION IN PVC GEOMEMBRANES

10/26/2004

T. D. Stark, Ph. D, P.E, H. Choi and P.W Diebel

57TH CANADIAN GEOTECHNICAL CONFERENCE

This paper discusses the three mechanisms of plasticizer migration and the factors influencing these mechanisms, such as plasticizer molecular weight and linearity of plasticizers. The paper recommends that a minimum average plasticizer molecular weight of 400 be used to ensure long-term plasticizer retention in the field.

Methane gas migration through geomembranes Methane gas migration through geomembranes

5/10/2004

T. D. Stark, Ph. D., P.E and H. Choi

Geosynthetics International

This technical note reviews gas transport mechanisms through flexible geomembranes by measuring methane gas transmission rates, permeance and permeability coefficient of PVC, LLDPE and HDPE geomembranes. A field design chart for estimating methane gas transmission rates for different geomembrane thickness and material is shown that can be used by landfill designers.

State-of-the-art report: GCL shear strength and its measurement State-of-the-art report: GCL shear strength and its measurement

3/20/2004

P. J. Fox and T. D. Stark

Geosynthetics International, 2004 11 No. 3

This paper provides information on shear strength and shear strength testing of geosynthetic clay liners. Additionally, the paper provides recommendations for the selection of design failure envelopes and information on GCL shear testing programs as well as improvements and future research needs.

Low-temperature air channel testing of thermally bonded PVC geomembrane seams Low-temperature air channel testing of thermally bonded PVC geomembrane seams

1/1/2004

T. D. Stark, H. Choi and R. W. Thomas

Geosynthetics International, 2004, 11, No. 6

The objective of this paper is to develop a procedure for air channel testing of dualtrack thermal seams at low sheet temperatures and recommendations for reducing destructive testing of field PVC geomembrane seams. Thus the proposed relationship and equation allow the seam peel strength to be determined from the field air channel testing without conducting destructive tests.

Occurrence and effect of bentonite migration in geosynthetic clay liners Occurrence and effect of bentonite migration in geosynthetic clay liners

11/26/2003

T. D. Stark Ph. D, P.E., H. Choi and R. Akhtarshad

Geosynthetics International 2004 11, No. 4

Since the introduction of geosynthetic clay liners (GCLs) to waste containment facilities, one of the major concerns about their use has been the hydraulic equivalence to a compacted clay liner as required by regulations. This paper presents field case histories that confirm the laboratory observations of bentonite migration and the effect of bentonite migration on hydraulic equivalence and contaminant transport through a GCL

Reduction of destructive tests for PVC seams Reduction of destructive tests for PVC seams

3/1/2003

Richard W. Thomas and Timothy D. Stark

GFR, March 2003

One of the current research topics being pursued by the PYC Geomembrane Institute (PGI) is the thermal welding and subsequent air channel testing of PYC geomembrane seams, which is the focus of this article. Other active research projects include the long-term performance ofPYC geomembranes using field case histories, shear behavior of PYC geomembrane interfaces, puncture characteristics of PYC geomembranes, and the chemical resistance ofPYC geomembranes. These projects will be discussed in future articles.