Busy A1 Buckden Roundabout Receives Essential Maintenance Work
Starting in June LMS Highways assisted in the A1 Buckden Roundabout major renewal project which consisted of resurfacing, road stud replacement and line marking. LMS Highways were on site to provide the concrete bay and deep surface removal, sub-base replacement and disposal portion of this project.
This is a busy section of the A1 so overnight working was used for the road studs and white lining to reduce any disruption for road users. However the resurfacing work required partial and full closures of the roundabout due to complexity and depth of the work required.
The removal of the existing surface was essential maintenance work to improve the driving quality and safety for road users. Throughout the 4 shifts LMS Highways were working on the A1 roundabout they removed a total of 350 Tonnes of concrete and installed approximately 160 Tonnes of type 1 sub-base in preparation for a new asphalt surface to be laid.
Type 1 sub-base is generally a 40mm graded to dust material that is laid and compacted to form a level stable construction layer as a platform for asphalt or concrete and is typically used in the construction of highways, car parks, footways and hard standing areas.
The existing concrete surface was removed using a lifting bucket which allowed for large sections to be removed as one complete piece and lifted straight into the disposal truck. Once the top layer of concrete had been removed, the deeper layers of sub-base and soil were removed and replaced with the type 1 sub-base stone. This was then levelled out with a process of hand levelling the stone before proceeding with rollers and wacker plates to further compact the sub-base.
Drop test are then completed to reveal if there are any weak spots before starting the next layer which is installed on top of terram. Terram is typical used to preventing intermixing of granular sub-base and subgrade layers and extending the service life of unbound materials.
Once the final layer of stone has been installed, levelled, compacted and tested once more, the underlaying sub-base can be signed off as sufficiently prepped to LMS Highways’ high standard and handed over to the next sub-contractor to install the new asphalt surface and the finishing touches such as road marking and studs.