| Slags of varying GaO content, having same SiO,fAl,O, ratio were hydrated
in presence of varying proportions of lime and mixtures of lime and gypsum for
different periods. The hydrated materials were subjected to DT A. When slags were
hydrated in presence of lime only there appeared tetracalcium aluminate hydrate
in all cases. Tobermorite and hydrogarnets were also possibly formed. Absor~
tion of lime was indicated in all cases. This decreased with incnease of GaO in
the slag and increased with time. When slags were hyd7'ated in presence of lime
and gypsum, the compounds identified were ettringite, crystalline solution of 'lowsulfate'
aluminate sulfate double salt and tetracalcium aluminate hydrate. The former
changed over to the latter when the proportion of gypsum in the mixture was
low and lime in the mixture or GaO in the slag was high. Absorptz'on of lime
during hydration in presence of lime and gypsum was always more than in presence
of lime only and this increased with acidity of slag and with time. An explanation
of the relative behaviour of different slags towards absorption of lime has been
offered. A possible mechanism of slag activation is postulated. |
