ACI Concrete International · 1989 · 11 citations · 0 references
EngineeringMaterials EngineeringMaterials ScienceBuilding MaterialsConstruction MaterialsStructural MaterialsCementitious MaterialsConcrete MaterialsConcrete TechnologySilicate MineralsAggregate Replacement In ConcreteAggregate StrengthConcrete StrengthConcrete Strength DevelopmentHigh-strength ConcreteMortar PermeabilityPermeability Of Cement PastePortland Cement
A new silica fume admixture in liquid form has been developed that is easier to handle than conventional powder forms. With this product, consistently high strength can be obtained regardless of portland cement source. The strength increase does not appear to be related to reduced porosity. The permeability of concrete is reduced when this new admixture is used. The use of high-strength aggregate did not increase mortar strength. It was found that in concrete made with the new admixture, a water layer does not form around the aggregates, and the amounts of calcium hydroxide and ettringite are reduced, leading to a stronger interfacial paste. Silica fume does not densify concrete in the usual sense, but enhances the paste-aggregate bond, which is usualy the weakest part of concrete.