1. Abir Al-Tabba, World Economic Forum, available at www.weforum.org, downloaded on 11/02/2019.
2. Supplementary Cementing Materials for Concrete, SP-86-8E,1987
3. Reducing the environmental impact of concrete;Mehta;Concr Int,2001
4. American Coal Ash Association, Inc Web resource http://www.ACAA-USA.org.
5. Federal Highway Administration, Fly Ash Facts for Engineers, FHWA-IF-03-019, June 2003.