Maintenance and repair of steel reinforced concrete structures by galvanic corrosion protection-field experiences over 10 years

Abstract

A galvanic zinc anode system, composed of a zinc mesh embedded into a proprietary solid matrix with ion exchange properties, was developed by CAS. The solid matrix of the embedded zinc anode system (EZA) is based on a tecto-alumosilicate-binder containing additives that prevent passivation of the zinc anode, assure high and durable galvanic activity of the zinc anode and high and durable adhesion towards the concrete overlay. The efficiency of the EZA, applied to concrete members of four types of civil structures-abutment of a road bridge in the Styrian Alps in Austria (2007), support-beams for the bearings of four viaducts in Den Hague in the Netherlands (2009) and a parking deck in Saas Fee in Switzerland (2011), was monitored with embedded reference cells and macro cell sensors. Data collected over a period of up to 10 years show that the EZA protects the steel reinforcement efficiently and reliably. An advanced EZA system-based on the novel shrinkage controlled EZA binder (SEZAC) covered with a novel water vapor permeable epoxy/PU membrane was installed July 2017 at the tunnel entrance of a federal road in the Styrian Alps. The EZA exposed to harsh weathering conditions proves to be efficient in protecting the steel reinforcement from corrosion.