EFFECTS OF SPECIFIC SURFACE AREA OF GROUND GRANULATED BLAST-FURNACE SLAG ON PROPERTIES OF HIGHLY SULFATED SLAG CEMENT MORTAR

摘要

Mortar prepared using ground granulated blast-furnace slag cement is considered to be usable for such applications as underground concrete structures, which are unlikely to be affected by carbon dioxide, and structures exposed to environmental conditions where the concrete structures will be subject to chemical reactions of such salts as sulfates. The authors studied effects of specific areas (4000, 8000 and 15000 cm~2/g in this study) of ground granulated blast-furnace slag on the cement mortar prepared using cement of high sulfate slag content. First, in this study, it was intended to examine the ratios of three components of the cement mortar : ordinary portland cement, ground granulated blast-furnace slag and gypsum dihydrate or anhydrous gypsum. As a result, the ratios of 0.05:0.80:0.15 (by weight) were found to be appropriate for the mortar. Next, on the basis of this finding, the authors studied properties of thus prepared mortar, including compressive strength, resistance to sulfate and acid attack, thermal resistance and drying shrinkage. The results proved that the larger the specific surface area of the ground granulated blast-furnace slag, the more the properties of the mortar improve, with exception of drying shrinkage, which reduces with decrease of the specific surface area of the blast-furnace slag.