Blended Cement Systems with Zeolitized Silica Fume

In this paper the properties and the hydration of Portland cement pastes containing zeolitized silica fume were studied . Hydrosodalite was obtained by zeolitization of silica fume. XRD, DSC, SEM and energy-dispersive X-ray spectroscopy were used as investigation methods. The compressive strength of hardened cement paste was measured after 28 days. The levels of  cement replacement by  additives were 5 %, 10 % and 15 % by weight in the specimens. Changes in the strength of hardened cement paste were observed. The influence of additives on hydration rate and hydration temperature was also observed. Both 1Hs (hydrosodalite) and 2Hs (modified hydrosodalite) additives accelerate the hydration of the cement paste. The highest hydration temperature was achieved in a mixture with 5 wt. % 1Hs additive and with 10 wt. % 2Hs additive. The microstructure of hardened cement paste specimens with 1Hs and 2Hs additive is denser compared with reference specimens without the additives. The maximum compressive strength of the specimens with 10 wt. % of 2Hs reached up to 101 MPa under laboratory conditions. DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7018