NUCLEATION AND POZZOLANIC FACTORS IN STRENGTH DEVELOPMENT OF CLASS-F FLY-ASH CONCRETE

A new model for the analysis of strength development of a Class F fly ash concrete is presented The analysis shows that the contribution of that fly ash to strength development is dependent on two parameters of the mix. These two parameters - nucleation and pozzolanic factors - fully conform to the effects of proportioning the fly ash mixes. These two parameters are found to be adequate to account for the strength development of fly ash concrete. The results indicate that the methods for the design of fly ash concrete based on a single parameter like the ''cementing efficiency '' may not be capable of modeling the strength development accurately. The results also show that the strength contribution up to 28 days can be broadly attributed to nucleation factor after 28 days to pozzolanic factor. The onset of pozzolanic reaction is found to depend on the fly ash/cementitious ratio of the mix.