This question came up sometime between 2010 and 2012, during the great Evergreen sidewalk debate. I did not have the answer then, and this article crossed my newsfeed this morning, so I am placing it here.
https://www.bloomberg.com/news/articles/2019-06-23/green-cement-struggles-to-expand-market-as-pollution-focus-grows
Synopsis of the EVERGREEN AVENUE in Homestead Valley "SAFE ROUTES TO SCHOOLS" Project
