Reduced environmental impact for GCCM channel remediation project in South Wales
Location of work/project:
Bedwas Colliery channel, Caerphilly, Wales
Concrete Canvas Ltd.
Dilapidated sections of an existing concrete drainage channel on the former Bedwas Colliery site were relined with Concrete Canvas® GCCM. A solution had been required to provide erosion and scour protection and extend the life of the network of drainage channels and effectively manage surface runoff.
Bedwas Colliery is a 20-hectare spoil tip which forms part of the historical mining legacy within the Caerphilly Basin in South Wales. The Colliery opened in 1913, producing up to 675,000 tonnes of coal each year before its closure in 1985. The overburden and rock generated by the mining activity formed the basis of the existing spoil tip.
The site, now managed by Caerphilly County Borough Council (CCBC), has a network of drainage channels which manages surface runoff. Due to the high flow of water through the existing channels, heavy scouring had occurred in places, leading to erosion of the concrete and exposing the reinforcement below. Two sections of channel were proposed for lining with Concrete Canvas® (CC), each measuring around 1000 linear meters with varying profile widths.
The channel sections requiring lining were situated on a hilltop, with access along a steep track. In order to simplify logistics and mitigate environmental impact, small access routes were created and most of the works were carried out from inside the channel itself.
The design specification process was completed as a collaboration between the client CCBC, Concrete Canvas Ltd, the contractor, Walters and Hilti. Bulk rolls of the 5mm and 8mm thick variants of CC were specified (CC5™ and CC8™); CC5™ was installed in areas where the damage was less extensive, while CC8™ was installed in areas where the reinforcement was exposed or flow rates were higher and greater scour protection was therefore required. Hilti fixings were used to secure the CC to the concrete channel.
6500m² of Concrete Canvas® GCCM were installed in six weeks, despite poor weather conditions. CC has a delayed setting time of 1-2 hours, allowing it to be installed in wet weather, saving time in comparison to traditional solutions which would require works to pause during rainfall.