Abstract:
The homogeneous state of the concrete in the fresh state has consequences on their properties in the
hardened state. The use of pozzolanic concrete must be carefully evaluated, because the physical and
chemical differences of each pozzolan have consequences on concrete hardened state properties. In this
work, two physical and chemically different pozzolans were used to evaluate the effect on concrete
microstructure and its basic hardened state properties. Scanning electron microscopy (SEM) was used
and can be an effective tool in the analysis of the microstructure allowing a better understanding of
the properties of concrete in hardened state. It allows showing that the differences in the two pozzolans
(metakaolin and diatomite) promote different microstructures as well as different final properties of pozzolanic
concrete. Moreover, it was also shown that the use of a water reducing agent, to adjust workability
instead of water, promotes an improvement in both the microstructure and the hardened state
features such as porosity and mechanical strength.