abstract
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In the present paper, pH of the aqueous solution contacting hydrated low-alkalinity cement was measured and the chemical mechanism to maintain the moderate pH was discussed.
The low-alkalinity cement was prepared by mixing 3CaO・3Al2O3・CaSO4 containing clinker, anhydrite and blast furnace slag. Solubility of hydrated cement paste was measured to investigate the effect of blast furnace slag. The Measured pH of the liquid phase contacting hydrated cement paste was in the range of 10.4 to 12.3 after 66 weeks. The composition of the hydrated cement paste was estimated from the chemical composition of the cement. The Measured pH of the liquid phase was compared with that evaluated from the chemical composition of hydrated cement and from the solubility data of calcium silicate hydrate (C-S-H gel). It was found that the measured pH agrees well with the evaluated pH.