GCL is Natural Material,well duiability,non-toxicity, ... High expansion rate,high water absor Geosynthetic Clay Liners (GCL) are high performance needle punched enbironmental reinforced composites which ... properties make the products ideal for many projects.Features:GCL is Natural Material,well duiability,non-toxicity,no corrosion ... after Wetting ASTM D 5321 ≥24Kpa typical GCL(Geosynthetic Clay Liners)