A449 Coldra–Usk rehabilitation

The UK's first overlay to a life-expired concrete pavement using a continuously reinforced concrete pavement (CRCP) has been successfully completed while maintaining traffic flows on the busy Midlands Link to South Wales. The 2-year Welsh Office (now The National Assembly for Wales) contract designed and administered by Burks Green for the major rehabilitation of 12·5 km of this two-lane dual trunk road has incorporated the first full-scale use of exposed aggregate, ‘whisper concrete’. The tyre–road interface noise levels have been reduced by between 2 and 6 dB(A) compared with the adjoining sections of carriageway, which were replaced using CRCP with conventional brushed concrete surface. SIAC Construction (UK) Ltd has undertaken the construction using the first two-layer slip from paving machine in the UK and the first produced by US plant manufacturers Gomaco. The contract has also seen the first successful use in the UK of a continuous-mix plant to produce pavement-quality concrete. The Aran mix plant from Australia is the first in the UK and was used to produce the top and bottom layer mix designs for the monolithic pavement slab. Exposed aggregate concrete is now required on all new high-speed roads in England, where concrete is provided as the running surface, and similarly in Wales unless in a non-environmentally sensitive area.