Approval of calcium nitrate as a concrete admixture in Germany

No provision is made in Germany – as opposed to practically all other countries in the world – for the utilisation of calcium nitrate (CN) as a concrete admixture. This is based on a regulation in clause 5.2.6 of DIN 1045-2, the standard for reinforced concrete. The historical background is an increased fear of stress corrosion risk and of a negative effect on the environment. This article will clarify the reasons behind this and outline experiments and results which clearly show that no increased risk arises with the proper utilisation of calcium nitrate – neither for building structures nor the environment. On the contrary, employing calcium nitrate can be very advantageous in constructing with concrete. The recently granted general building authority approval for a CN accelerator means that these advantages can now be utilised for the first time in Germany as well.

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