Strength and deformability of different types of geosynthetic barriers

Abstract

Introduction. Water engineering facilities utilize geosynthetic barriers of various materials, but the most common are polyvinylchloride (PVC) and polyethylene (PE) considered to be the most efficient. However, the utilization of thermoset geosynthetics (PVC and PE) as watertight elements of the geosynthetic barriers of earth dams has also a number of drawbacks. In the course of time, PVC can lose its properties due to plasticizer loss, whereas PE is susceptible to cracking at thermal impacts. That is why it is necessary to consider geosynthetic barriers of other types as alternatives. For this purpose, we studied the deformability and the strength of geosynthetic barriers of thermoset material (chlorosulfonated polyethylene — CSPE), as well as of a rubber-type synthetic material (ethylene-propylene diene monomer — EPDM). Materials and methods. Sample testing of geosynthetic barrier materials for monoaxial extension was conducted by means of a tensile-testing machine, which records during the experiment the changes of the tensile force and the longitudinal extension. The changes of the cross-section area of the samples were measured by means of a digital side caliper. Results. It was determined that of the considered geosynthetic barrier types (PE, PVC, CSPE and EPDM) the strongest one is the reinforced CSPE type and the most deformable is the EPDM barrier. Reinforced CSPE geosynthetic barrier has a tensile strength above 100 MPa, it is approximately 5 times higher than that of PVC and PE barriers. By deformability, reinforced CSPE barrier is similar to PE barriers. An EPDM geosynthetic barrier has the linear deformation modulus around 1 MPa, it is capable of a multiple extension without loss of strength. Conclusions. By strength vs. deformability ratio, EPDM geosynthetic barriers can compete with PVC barriers.