Influence of Silica Fume Replacement of Cement on Physical Properties and Resistance to Sulfate Attack, Freezing and Thawing, and Alkali-Silica Reactivity

The results are presented of a series of tests of the physical properties and durability of pastes, mortars, and concretes made with silica fume replacements for part of the portland cement: silica fume reduced the permeability of cement pastes and concretes; silica fume reduced the size of pores and total porosities of both cement and concretes; silica fume reduced the leachable calcium hydroxide contents of cement pastes; silica fume reduced the level of alkalies leached from the pastes; silica fume improved the resistance of ASTM C 441 Pyrex mortar bars to deleterious expansion; silica fume provided resistance superior to that of a sulfate resistant portland cement in ASTM C 1012 tests for sulfate resistance; and silica fume provided resistance to freezing and thawing to a series of high-strength, non-air-entrained concretes.