Method development for the particle size analysis of supplementary cementitious materials

Fineness of supplementary cementitious materials (SCMs) influences the porosity and the pore size distribution of the hydrated cement paste and moreover the service life and durability of a concrete structure. the characterization techniques that are currently used for the determination of particle size distribution of SCMs are the usual ones that are used for the determination of fineness of cement. This includes sieving, air permeability, laser diffraction, and BET. Nevertheless, in the case of SCMs these techniques are under question. The present study attempts to provide a specific method developed for the determination of particle size of fly ash by using the laser diffraction technique, which is considered to be the most appropriate technique for the measurement of fineness of SCMs. For this purpose all the parameters of the technique (model, sample dispersion, sample quantity, optical parameters) are taken into account. After several trials those parameters which provide the best fitting were chosen and an accurate, reproducible and routine method was established