The effect of pozzolanas on the tricalcium aluminate hydration

Gypsum in Cement

“…When a solution is viscous or, because of the geometric scale of the interface, there is little or no bulk mixing, the instantaneous supersaturation ratio at the interface with respect to the insoluble product can attain high values and be greatly in excess of the critical ratio for homogeneous nucleation. This would also confirm the observations of Collepardi et al [29] and Mehta [37,38] according to whom only colloidal ettringite has a delaying effect on C 3 A hydration. So there is a gelatinous precipitate capable of forming a continuous membrane.…”

“…[29], who, substituting CaSOu . Frigione formation of such a structure decreases the number of active dissolution sites and, thus, the rate of C3A dissolution decreases.…”

Quick monitoring of pozzolanic reactivity of waste ashes

“…It is well known that pozzolan, in the presence of moisture, will chemically react with Ca(OH) 2 (ASTM C 618, 1999;Neville, 1999). Beside, pozzolans react also with C 3 A or its products of hydration (Collepardi et al, 1978). To simulate the aqueous phase of a pozzolan-concrete mixture, products from the hydration reaction of cement with water were used as reactant when monitoring the pozzolanic reactivity of tested pozzolan.…”

Hydration properties of boron modified active belite cement concrete

“…Thus, anyone in concrete and/or cement industry has to take into consideration not only the cement hydration process, but also the curing process and period. Due to potential of cement based composites wide usage, all over the world, concrete manufacturers are very interested in that type of cement and its effect on the concrete properties [1][2][3][4][5][6][7][8][9][10][11].…”