Potential applications of galvanised reinforcing steel in clinker-reduced binder systems, taking specific corrosion phases into account

• Applicants: Dr.-Ing. Gino Georg Günther Ebell; Dr.-Ing. Christian Helm
• Subject Area: Construction Material Sciences, Chemistry, Building Physics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 574798826

In North America, numerous positive experiences have been gained with galvanized reinforcement in traffic constructions. The comparatively low monetary cost has resulted in significant extensions of service life. In structures designed with conventional reinforcement, chloride-induced macro cell corrosion is often the most damaging form of corrosion due to the cathode-to-anode ratios that favor corrosion. Galvanized reinforcement can prevent pitting corrosion initiation on the steel substrate after localized complete dissolution of the zinc layer. This is based on an inverse area ratio between the anode and cathode and a lower driving voltage between them. This operating principle has already been proven in cathodic corrosion protection with galvanic anodes. With regard to the current challenges of developing sustainable construction methods, so-called alternative binders, among other approaches, are currently the focus of materials research. The subject of the present research proposal includes clinker-reduced cements with calcined clay (metakaolin) as a substitute. While the use of CEM I-based highly substituted cements is currently severely due to disadvantageous properties for the corrosion behavior of reinforcing steel in exposure classes XC and XD, galvanized steel offers promising potential for use here. Expanding the range of application for alternative binders through the use of galvanized reinforcing steel appears to be a logical step and offers significant application potential. However, this potential can currently not be exploited due to a lack of fundamental knowledge and normative constrains. The basis for enabling the application is therefore a deeper understanding and confirmation of the theoretical predictions for these corrosion systems. Within the scope of corrosion studies, the corrosion behavior of galvanized reinforcing steel in the various binder compositions will be investigated in detail and compared with that of conventional reinforcing steel. The experimental investigations are complemented by numerical simulations, which allow the transfer of the conclusions to a larger number of surface ratios at macro cells. The investigations conclude in a corrosion model, which can be used to quantitatively evaluate the benefit of galvanizing as a gain in service life.

• DFG Programme: Research Grants