Macrocells monitoring

Steel can be obtained due to the small cathode/anode ratio. This macrocell monitoring system has been installed since 1990 into tunnels, bridges, foundations and other structures exposed to aggressive environments [5]. Similar systems have been developed and are on the market (6). 

Figure 17.6 Schematic view of macrocell current measurements between an Isolated piece of rebar (anode) and the surrounding rebar network (cathode). In the open-circuit condition the potential difference and the resistance between the two electrodes can be monitored [15]... 

M. Raupach, P. Schiessl, Macrocell (10 sensor systems for monitoring the corrosion risk of the reinforcement... 

An alternative approach, which reintroduces the theme of long-term corrosion monitoring, is the embedding of macrocell devices. This includes galvanic couples of different steels (Beeby, 1985) or embedding steel in high chloride concrete to create a corrosion cell, as is popular in cathodic protection monitoring systems, particularly in North America (NACE, 2000). 

Zero-resistance ammetry. The macrocell current measured between embedded rebar probes has been used for monitoring the severity of corrosion. This principle has been widely used, as part of the ASTM G102-92 laboratory corrosion test procedure, with current flow between probes located at different depths of cover. For the monitoring of actual structures, a similar approach has been adopted. Here, current flow has been measured between carbon steel probe elements strategically positioned at... 

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