Abstract:
The alkali-silica reaction (ASR) consists of the reactive process in which aggregates containing
reactive silica constituents react with alkalis and hydroxyl ions present in cement pore solution. It is
suspected that some superplasticizers admixtures can contribute to the increase in concrete alkalinity.
Literature presents some contradictory results about its influence on ASR. In this work the influence
of superplasticizers admixtures in mortars prepared with pozzolanic admixtures was evaluated by
accelerated mortar-bar tests and atomic absorption spectrophotometry. In the pozzolanic mixes the
cement was replaced by 15% (weight %) of metakaolin or silica fume. Three superplasticizers
admixtures (melamine, lignosulfonate and naphthalene) were utilized in three levels. The results show
the mortars with the melamine based superplasticizers presented the lower content of soluble alkali
and expansion. It is concluded that this admixture could be the most