Значение и использование

4.1 Designers/specifiers of geosynthetics should evaluate geosynthetic durability as an integral part of the geosynthetic specification/selection process. This guide is intended to guide a designer/specifier through a systematic determination of degradation concerns based on the intended geosynthetic function or performance characteristic. This guide then provides a guide to select available test methods for experimentally evaluating geosynthetic durability and to identify areas where no suitable test exists.

4.2 This guide does not address the evaluation of degradation resulting from manufacturing, handling, transporting or installing the geosynthetic.

Область применения

1.1 This guide covers a designer/specifier through a systematic determination of those factors of the appropriate application environment that may affect the post-construction service life of a geosynthetic. Subsequently, test methods are recommended to facilitate an experimental evaluation of the durability of geosynthetics in a specified environment so that the durability can be considered in the design process.

TABLE 1 Functions^A and Other Performance Characteristics^B

Containment^B (C)—A geosynthetic provides containment when it encapsulates or surrounds materials such as sand, rocks, and fresh concrete.^C

Filtration^A (F)—A geosynthetic performs the filtration function when the equilibrium geotextile-to-soil system allows for adequate liquid flow with limited soil loss across the plane of the geotextile over a service lifetime compatible with the application under consideration.

Fluid Barrier^A (FB)—A geosynthetic performs the fluid barrier function when it essentially eliminates the migration of fluids through it.

Fluid Transmission^A (a.k.a. drainage)—A geosynthetic performs the fluid transmission function when the equilibrium geotextile-to-soil system allows for adequate flow with limited soil loss within the plane of the geotextile over a service lifetime compatible with the application under consideration.

Insulation^B (I)—A geosynthetic provides insulation when it reduces the passage of heat, electricity, or sound.

Protection^A (P)—A geosynthetic, placed between two materials, performs the protection function when it alleviates or distributes stresses and strains transmitted to the material to be protected.

Reinforcement^A (R)—A geosynthetic performs the reinforcement function when it provides often synergistic improvement of a total system's strength created by the introduction of a tensile force into a soil (good in compression but poor in tension) or other disjointed and separated material.

Screening^B (Scr)—A geosynthetic, placed across the path of a flowing fluid (ground water, surface water, wind) carrying particles in suspension, provides screening when it retains some or all soil fine particles while allowing the fluid to pass through. After some period of time, particles accumulate against the screen which requires that the screen be able to withstand pressures generated by the accumulated particles and the increasing fluid pressure.

Separation^A (S)—A geosynthetic placed between dissimilar materials so that the integrity and functioning of both materials can remain intact or be improved performs the separation function.

Surface Stabilization^B (SS)—A geosynthetic, placed on a soil surface, provides surface stabilization when it restricts movement and prevents dispersion of surface soil particles subjected to erosion actions (rain, wind), often while allowing or promoting vegetative growth.

Vegetative Reinforcement^B (VR)—A geosynthetic provides vegetative reinforcement when it extends the erosion control limits and performance of vegetation.

^A Functions are used in the context of this guide as terms that can be quantitatively described by standard tests or design techniques, or both.^B Other performance characteristics are qualitative descriptions that are not yet supported by standard tests or generally accepted design techniques.

Note—during the placement of fresh concrete in a geotextile flexible form, the geosynthetic functions temporarily as a filter to allow excess water to escape.

1.2 This guide is not intended to address durability issues associated with the manufacturing, handling, transportation, or installation environments.