Goosecroft Underpass, UK

THE PROJECT

The A9 is a major road in Scotland running from the Falkirk council area in central Scotland to Scrabster Harbour, Thurso in the far north, via Stirling, Bridge of Allan, Perth and Inverness. At 273 mi, it is the longest road in Scotland. The A9 Goosecroft underpass bridge in Stirling's City-Centre had areas of delaminating concrete due to the expansive corrosion of the steel reinforcement within it. The client was seeking a repair solution which could help the speedy reinstatement of the defective concrete, with a minimum of disruption to the road network. Fosroc have a longstanding relationship with the Concrete Repair Association member Concrete Repairs Limited (Scotland), which has seen the two companies work alongside on a wide range of projects across the infrastructure network. The Goosecroft underpass project required a BS EN1504 compliant mortar, that could be applied in a dry-spray process.

THE SOLUTION

Fosroc’s Renderoc DS dry spray mortar was specified as the ideal solution as it met the project requirements in terms of quality certification and preferred application method. Designed specifically as a repair solution for areas such as beams, columns and panels on buildings, bridges, tunnels and marine structures, it can be used for both isolated and large area repairs, and as wide scale overlay system to increase cover to the reinforcement. With a market-leading low rebound, high resistance to carbon dioxide, and excellent bond to concrete, Renderoc DS offers many benefits over alternative solutions. In addition to the strengthening, Renderoc DS’s integral fibres increase fire resistance, by melting in the event of a fire and allowing from moisture and steam to escape. This prevents pressure build up and eventual spalling of material. It is a National Highways approved product that can also be used for cathodic protection systems.

THE BENEFITS

The use of Renderoc DS at Goosecroft underpass allowed the applicator to proceed within the rigid timescales, ensuring the carriageway closures were minimised. The key to this from a product efficiency perspective was selecting a mortar with minimum rebound levels. This in-turn sped up the mortar reinstatement, while also ensuring less clean-up and landfill. The project was undertaken during a year of strict Covid-19 restrictions, but the strict project timescales were achieved safely with site assistance provided by Fosroc as required.