Quantitative kinetics of pozzolanic reactions in coal/cofired biomass fly ashes and calcium hydroxide (CH) mortars

This document comprehensively studies the quantitative kinetics of pozzolanic reactions of class C and F and cofired biomass fly ashes with Ca(OH)2 (CH) under carbonation free conditions. The grams of chemically combined CH per gram of fly ash increase with the CH mixing ratio, curing temperature and curing days. The chemically combined mass ratio is approximated at 30/70 (CH/fly ash), although it varies slightly from ash to ash. The quantitative kinetics shows that class C and F, cofired biomass and pure biomass fly ashes share the diffusion mechanism. Therefore, the cofired biomass fly ash needs reevaluation in rather than exclusion by ASTM C 618 from concrete for its “noncoal” origin.