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Geobear’s Innovative Solution for the Warford and Watercourse Viaduct

This case study explores Geobear’s successful low-carbon intervention at the Warford and Watercourse Viaduct in Cheshire, Runcorn, a project commissioned by Network Rail. The primary challenge was to waterproof the viaduct spandrels and fill voids to prevent rainwater ingress without causing environmental harm to the underlying watercourse. Geobear’s environmentally friendly geopolymer solution not only met, but exceeded these requirements, offering a fast, efficient, and effective resolution. Furthermore, the Geobear solution provided a 35% reduction in carbon emissions compared to foam concrete.

Background & Challenge

Project Overview

  • Project Title: Warford and Watercourse Viaduct
  • Client: Network Rail
  • Location: Cheshire, Runcorn

The viaduct’s spandrels, featuring inspection chambers connected by foxholes, posed a significant challenge. These chambers, classified as confined spaces, needed void filing and waterproofing beneath the track, with a focus on avoiding future inspections and preventing rainwater runoff from entering them.

The Need for an Innovative Solution

Network Rail required a solution that was quick to implement, complied with the route’s regulations, and was environmentally friendly, especially considering the viaduct’s position over a stream.

Alternative Solutions & Their Challenges

Options Considered

  • Foam concrete

Challenges with Alternatives

  • Potential for leakage through weep holes.
  • Environmental risks if materials leaked into the watercourse.
  • Longer curing times and complex application processes.

Geobear’s Solution


Geobear proposed using a geopolymer solution known for its rapid expansion, solidification, and curing properties.

Key Features of Geobear’s Approach

  • Environmental Benefit: The geopolymer is non-hazardous if it contacts water.
  • Operational Efficiency: It is five times lighter than cementitious grout, reducing structural load and offering quicker curing.
  • Application Method: Injection directly into the voids, allowing full visual verification.
  • Project Execution: Ground-level access was utilised to maximize work efficiency and avoid time-consuming rail possessions.

Plan shows foxholes and injection locations


Environmental Safety

The geopolymer’s non-hazardous nature ensured safety for the underlying watercourse.

Speed and Efficiency

The solution allowed for faster application and curing, significantly saving time compared to other methods.

Operational Advantages

The use of direct ground-level access facilitated more effective work shifts.

Client Satisfaction

Network Rail’s satisfaction with the project’s success has led to considering Geobear for future, larger-scale projects.

Carbon footprint

The Geobear geopolymer approach significantly reduces carbon emissions compared to alternative methods; in this context, the likely alternative is foam concrete. To quantify the carbon emissions, we reference data from previous reports by Carbon Footprint, which calculated the kilograms of CO2 equivalent (CO2e) released per square meter of installed geopolymer in a rail environment as 185 kg. In comparison, a study by the University of Waterloo, Canada, found that foam concrete releases 298 kg of CO2e per cubic metre. Based on these figures, the total carbon emitted for a project using the geopolymer was 32,681 kg, whereas using foam concrete, it would have been 51,032 kg. This represents a 35% reduction in carbon emissions when opting for a Geobear geopolymer solution.

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