Umweltverträglichkeit von Betonzusatzmitteln / Environmental Impact of Superplasticizers

A chemical risk assessment for the use of concrete admixtures was performed for the case of naphthalene sulfonate condensate (NS) which is a widely used superplastizicer. As a result of its use as a concrete admixture, NS and its degradation products in condensed naphthalene sulfonates can be emitted into the environment. In relation to other products such as detergents, the emissions of NS are classified as very low. The most important emissions of NS originate during its production and during the washing of concrete mixers when the wastewater is allowed to enter the sewers. Future emissions of naphthalene sulfonates are predicted for the case of storage/disposal of concrete waste, or the use of NS-containing concrete waste in road construction. The predicted concentrations of NS and naphthalene sulfonates in Switzerland (either on the regional or local scale) are expected to be below the predicted no-effect concentrations (PNEC values or "safe" concentrations).