I generally apply the ACI volumetric mix design approach when calculating theoretical porportions. Fly ash, being a pozzolan, is commonly substituted for a portion of Portland cement in the mix. Accepting that the fly ash composition meets all ACI/ASTM/CSA criteria, can the fly ash be substituted at a 1:1 ratio with Portland cement (up to a limit of course) or should I be using a reduced equivalency ratio of say 1.0 lb fly ash : 0.75 lb Portland cement.
Thank you.
Thank you.