The galvanic corrosion protection (GCP) with a sacrificial zinc anode is a reliable method to protect reinforcement steel in concrete from corrosion induced by chloride. The working principle of GCP is the same as for zinc-air cell - similar to the Leclanche batteries from the 19th century:

A zinc mesh is embedded into a  proprietary solid electrolyte - the TAS-EZA electrolyte - and directly connected to the steel reinforcement.
The performance of the embedded zinc anode (EZA) may be monitored by monitoring macro-cell currents of into the concrete embedded macro-cell sensors with the proprietary LE-DAC system.

Galvanic corrosion protection of steel in concrete
Hardcopy available at Composite Anode Systems GmbH

Passive Corrosion protection with the galvanic EZA system