D. Bonen, A MICROSTRUCTURAL STUDY OF THE EFFECT PRODUCED BY MAGNESIUM-SULFATE ON PLAIN AND SILICA FUME-BEARING PORTLAND-CEMENT MORTARS, Cement and concrete research, 23(3), 1993, pp. 541-553
Citations number
17
Categorie Soggetti
Construcion & Building Technology","Material Science
A chemical and microstructural study has been carried out on Portland
cement mortars with and without silica fume subjected to magnesium sul
fate attack. The mortars appeared to be less durable than their counte
rpart pastes as indicated by greater surface deterioration greater dep
th of sulfate ingress, more extensive gypsum deposition, and a higher
degree of decalcification of the CSH gel. The plain (non-silica fume)
mortar was distinguished by massive deposition of gypsum. Preferred si
tes of deposition were around aggregates, in air voids and other cavit
ies. In the silica fume bearing mortar less gypsum was deposited. Neve
rtheless, the CSH of the silica fume bearing mortar experienced a high
er degree of decalcification than the CSH of the plain mortar. Based o
n occurrence of surface deterioration and cracking pattern, it appears
that silica fume addition did not improve durability. It is concluded
therefore that the decalcification of the CSH plays a major role in t
he deterioration process.