1 research outputs found
Evolution of the pozzolanic activity of a thermally treated zeolite
Zeolites generally show pozzolanic activity due
to their structural characteristics. The utilisation of pozzolans
as additions to cements results in added technical
advantages of the construction materials. In this study, the
pozzolanic activity of a thermally treated natural mordenite-
type zeolite from the Palmarito open-air deposit
(Cuba) was evaluated with respect to a non-treated zeolite.
Initially, a thermal treatment of the zeolite was performed
at different temperatures within the range 300–1000 C for
5 h in order to evaluate the better temperature of treatment.
Afterwards, the pozzolanic activity was determined for
each temperature after 7 days of reaction with a saturated
Ca(OH)2 solution that simulates the release of lime from
ordinary Portland cement during the hydration reaction.
The higher pozzolanic activity was achieved with the
thermal treatment performed at 300 C. Therefore, a further
study studied the evolution of the mineralogical phases
produced during pozzolanic reaction up to 90 days, carried
out with the zeolite treated at that temperature. Consumption
of Ca2? in solution and formation of C–S–H-like phases with low Ca/Si ratio were experimentally observed
as the main pozzolanic products. The thermodynamic study
confirms high reactivity of the zeolite at short-term and
chemical stability of the reaction products after 28 days.
The zeolite thermally treated at 300 C confirmed an
increase in the pozzolanic activity with respect to the nontreated
zeolite.Peer reviewe