In 2022 Tarmac appointed Recycled Roadways, one of the companies of the KKB Group, to facilitate the replacement of concrete carriageway during the A12/A14 upgrade works by Highways England.
We were tasked with recycling concrete broken-out from the existing trunk roads into new aggregate material to be used to form replacement pavements for each project. The concrete had been in situ on both roads since the 1980s and was being replaced with quieter-running asphalt surfacing.
We established sites at two locations in Stanway near Colchester and near Bury St Edmunds to process the waste concrete material from the A12 and A14 respectively. Each site contained integrated crushing and screening facilities with material fed and relocated using excavators and loading shovels.
Waste concrete planed out by the main contractors using a surface mining machines is transported to our sites arriving in either large breakout lumps or roughly 0-70 mm. This is loaded into impact/cone crushers (to minus 24mm) then fed into two-way screening plant to produce single-sized aggregate – either 0-10mm or 10-20mm.
Metal contaminants such as rebar and heavy steel dowel bars are removed magnetically during the primary crushing process.
The aggregate feedstock is then loaded into an adjacent batching plant to create cement bound material (CBM) - roadbase and/or basecourse which is delivered back to the sites and installed by surface paving machines.
Our crushing screening process is adjusted to generate standard 6F5 capping layer and Type 1 subbase as required.
Over 50,000 tonnes of concrete materials have been processed to date.