Question

Rank the following materials in order of their rate of hydration in a Portland cement binder system: fly ash, silica fume, slag

Answer 1

Solution:

1. There is a good linear relationship between the reaction degree of slag (or) fly ash (or) silica fume and hydration heat of a slag (or)fly ash (or) silica fume in Portland cement binder.

2. The hydration heat of per gram of slag or fly ash decreases with the increasing the dosage of slag or fly ash, the hydration heat of per gram of slag is clearly higher than that of fly ash at the same temperature due to sensitivity reaction of slag is higher than that of the fly ash.

3. The hydration heat of per gram of silica fume increases with the increasing the dosage of silica fume.

4. At 25 degree centigrade the heat of hydration of slag is higher then that of silica fume and the heat of hydration of silica fume is higher then that of fly ash.