This standard is drafted according to the GB/T 1.1--2009. This standard can take the place of GB/T 17643--1998: Geosynthetics -- Polyethylene geomembrane. The main differences of this standard from GB/T 17643--1998 are as follows.
1. More relevant terms and definitions are given.
2. Relevant requirements for the base resin are inserted.
3. High density rough polyethylene geomembrane for environment protection and linear low density polyethylene geomembrane for environment protection are inserted. Ethylene/vinyl acetate copolymer (EVA) geomembrane is deleted.
4. Requirements for length deviation, width deviation, thickness deviation and appearance quality are tightened.
5. Technical criteria of tensile breaking?strength, elongation?at?break, rectangular tear load, dimensional stability, OIT (Oxidative Induction Tine) are increased.
6. Requirements for density, tensile yield strength, yield elongation, anti-puncture strength, carbon black dispersion, 85℃ thermal aging and anti-UV are inserted.
7. Measures of thickness of exasperate geomembrane, coarse height of exasperate geomembrane, anti-puncture strength, carbon black dispersity, tension load stress cracks (tensile load test of incision under dead load), OIT (Oxidative Induction Time) under high pressure are inserted.
8. Water vapor penetration coefficient and low-temperature impact of high density polyethylene geomembrane for environment protection (GH-2 type) and linear low density polyethylene geomembrane for environment protection (G1-2 type) are not mentioned.
Geosynthetics is a general term of synthetic materials applied in the field of civil engineering.
Classification of geosynthetics changes with the development of new material and new technique. Ministry of Water Resources of China enacted "Technical code for application of geosynthetics" with other relevant departments in 1998 and classified the geosynthetics into four categories, namely the geotextile, geomembrane, geocomposite, and special materials.
