Gunform: A21 Panthurst Farm Armco Tunnel Refurbishment completed march 2025
Gunform International working for Freyssinet Ltd . Client :National Highways .Designers : Jacobs
Armco culvert/ Tunnel approximately 80metres long and 5to 6 metres in diameter
Gunform Carried out :
Cleaning works using high pressure water jetting
Installed new concrete blinding and reinforced concrete invert 120m3
Installed new Ramarch support sections (manufactured by ISS Ltd) and pre rolled steel reinforcement .
This enabled the new reinforced concrete lining to be free standing within the Armco Tunnel with no direct fixings into the Failing structure.
Application of 216m3 of C40/50 Sprayed concrete Lining 170/220mm thick as sprayed finish.
Install new access ramps
Concrete pumping/spraying distance up to 100metres .
Equipment used: Reed B20 concrete pump
Concrete supplier: Brett Concrete
