Patent ID: 8518176

Claim:
A method for making a blended fly ash Portland cement composition, comprising: mixing together (A) Portland cement and (B) pre-hydrated, unponded fly ash in a cement to fly ash ratio (C:FA) of 95:5 to 21:79 by dry weight to obtain a mix; the Portland cement and pre-hydrated, unponded fly ash mix comprising a source of soluble sulfate in an amount sufficient to sustain hydration of the Portland cement when water is added to the mix to initiate hydration of the Portland cement; pre-hydrated, unponded fly ash having a total alkaline earth metal content, when expressed in terms of molar equivalent of calcium oxide, of at least 10% based on total weight of the fly ash; and the pre-hydrated, unponded fly ash being pre-hydrated (i) by mixing the unponded fly ash in a body of water to obtain a fly ash slurry, the amount of the body of water being at least 10% by weight of the fly ash to allow partial or total dissolution of unhydrated, reactive calcium aluminate-containing phases and partial or total precipitation of calcium-containing hydrates; and (ii) allowing the fly ash to soak in the body of water, being at least 10% by weight of the fly ash, to allow the water-soaking fly ash to undergo peak exothermic reaction generated by the partial or total dissolution of reactive calcium aluminate-containing phases and partial or total precipitation of calcium-containing hydrates within the body of soaking water.