Granulated blastfurnace slag and Portland cement were first ground separately into samples of different fineness, covering the range 2500 to 6OOO cm2 g-l in Blaine areas. For each sample, various slag-cement mixtures were prepared using Portland cement with the same Blaine area. Paste-hydration of the various slag-cement mixtures was carried out at room temperature for different curing periods; the initial W/C ratios used were 0.30 and 0.40. From the results of combined (non-evaporable) water, free slag and free lime contents of the hardcned pastes at various hydration ages, and their relation to the development in compressive strength, the mechanism of the hydration process could be specified. The suggested mechanism includes six hydration stages; these are (i) pre-dormant, (ii) first dormant, (iii) first acceleration, (iv) second dormant, (v) second acceleration and (vi) diffusion period. The beginning and duration of each hydration period depended primarily on the fineness and the constitution of the slag-cement dry mixture.

No abstract

No abstract

No abstract