Based on the paper 'Investigation, Mitigation and Management of Corroding Bridge Joints in Leicestershire', presented at the Highways Maintenance Engineers Conference at Nottingham University, 7-9th September 1998.
Bridge structures are designed to last decades, but one persistent issue continues to threaten their durability: corrosion caused by salt-laden water leaking through joints. Over time, this accelerates the deterioration of embedded steel reinforcement, putting structural integrity at risk. A project on the M1 motorway in Leicestershire, UK, offers a compelling case study in how innovative engineering, specifically impressed current cathodic protection (ICCP), can address this challenge effectively and with minimal disruption.
Bridges built in the 1970s, though innovative for their time, included design features like half-joints and concrete hinges that have proven vulnerable. Water carrying de-icing salts seeps through joints, reaching deep into the structure and triggering corrosion.
Inspections revealed:
In some cases, corrosion was occurring in areas not detectable through standard surface inspections, making the problem even more dangerous.
Half-cell potential mapping (surface and deep-hole)
Chloride concentration analysis
Targeted drilling into critical joint areas
These tests confirmed that corrosion was most severe deep within the half-joints, especially near key structural interfaces.
To stop corrosion at its source, engineers implemented ICCP, a technique that applies a small electrical current to the steel reinforcement, preventing it from corroding.
A major challenge was delivering protection deep within the structure. The solution came in the form of conductive ceramic “discreet anodes”, inserted into drilled holes. This approach allowed engineers to target the most vulnerable zones directly, rather than relying on surface treatments.
The system didn’t stop at installation. It included a networked monitoring system that allows engineers to track corrosion rates in real time, adjust electrical current remotely, receive alerts if performance drops and manage multiple bridges from a central location. This marked an early move toward digitally managed infrastructure.
One of the most impressive aspects of the project was execution. Most work was done from beneath the bridge with minimal impact on motorway traffic and the system fully operational within schedule.
Following this success, similar systems were installed on additional bridges along the M1.
This project demonstrates a shift in infrastructure management.
From reactive repairs → to proactive, long-term protection
From manual inspections → to smart, remote monitoring
From disruptive works → to minimal-impact solutions
As infrastructure ages worldwide, approaches like ICCP offer a sustainable and cost-effective way to extend the life of critical assets.
