General director, CEMENTIR, Roma,
Director of laboratory, CEMENTIR, Napoli,
The sulfate resisting portland cement is obtained from a special portland cement clinker with low-tricalcium-aluminate content. In Western Europe another cement is used more for constructions in sulfate environments than portland low-tricalcium-aluminate cement, the blast furnace slag cement with slag content higher than 70%. According to ASTM standard Specification for Concrete Aggregates (C 33), when reactive alkali-aggregates are used, portland low-alkali cement is recommended. According to the European experience, the blast-furnace slag cement with slag content greater than 70% does not produce any expansion when used with stone materials of potential alkaline reactivity. This paper deals with the performances of blastfurnace slag cements tested for sulfate resistance and for alkali-aggregates reaction. The results obtained fully confirm the possibility of overcoming the risk of alkali-aggregate expansion and sulfate destruction by using blast furnace slag cements with high-slag content. The lower energy cost of blast-furnace slag cement, which can replace the special portland cement with low-tricalcium aluminate and low-alkali content, may favor its use.
Paper ID: CCA10250J