Diatomite powder as pozzolana active mineral admixture in mortar mix composition

The aim of the study was investigate the possible use of diatomite powder as a partial replacement of Portland cement in the production of cement mortar. Diatomite was used as 10% and 20% replacement by weight of cement while sand quantity and water dosage were kept constant. The particle size distribution of diatomite was researched on a laser diffraction principle, whereas its pozzolana activity was also studied. For the materials with diatomite as well as for control mortar, basic structural properties, compressive and flexural strengths, freeze–thaw resistance, dynamic modulus of elasticity, sorption and desorption isotherms were measured. The diatomite use led to the decrease in porosity, and thus to the increase in mechanical resistance of the tested mortars. On the other hand, the frost resistance of mortars with incorporated diatomite powder was lower compared to control PC-based mortar. The water vapor storage capacity of diatomite enriched mortars slightly increase compared to the control mix, but the maximum moisture storage remained low in general.