GMA techline answers from Bob Koerner
Subject: Alkalinity — I am working on a site where there is limestone bedrock. There may be some blasting required that could generate blasted rock fill.
Is there a concern with using limestone rockfill with HDPE or polyester-coated geogrids? (Mike, Virginia)
Reply: There is no concern over using the HDPE (or PP) geogrids in high alkalinity environments. Regarding the PET (assuming that the coating is not 100% complete or has been scratched during installation), there is a concern when the pH is more than 10. This may not be likely, but it is something you have to assess.
We will send a study to you regarding pH between masonry segmental wall units, which should be more active than limestone rock, I believe.