From the GMA Techline
Subject: Waterproofing membrane liner for a salt storage building We are required to specify the above to be installed beneath an asphalt pavement floor of a proposed salt storage facility. What would be an appropriate product and specification for installation in accordance with best industry practices? (Colin from New York)
Reply: I think that EPDM, fPP, LLDPE, or PVC geomembranes are all candidates. Specifications for the first three are at: www.geosynthetic-institute.org. I can get the fPP since it is currently suspended for some minor adjustments; and the PVC is available through the PVC Geomembrane Institute (PGI).
You will have to determine the thickness based on site-specific conditions.