By using activators, high-strength composite cement was
obtained which contained a large amount of BFS and fly
ash. The proper proportion for composite cement are detailed
as following: clinker 30±50%, BFS 30±50%, fly ash
10±20%, G 5%, N2%, and A (or E) 3±4%.
The effect of compound activators N and A (or E)
together was found to be better than that of a single one.
N increased the alkalinity of solution and promoted the
depolymerization of BFS and fly ash. A (or E) dissolved and
took part in hydration.
The main hydrate products were C±S±H gel AFt and Ca
(OH)2 crystallites, though little amount of the last in highstrength
cement. Under the influence of activators, Ca
(OH)2 went on to react with AlO4
5ÿ
and SiO4
4ÿ
depolymerized
from BFS and fly ash, to form more products and,
therefore, strengthen the structure of the cement stone.