While traditional methods of working would have likely required a two-week programme of night-time closures, Metrail teamed up with Otto Alte-Teigeler GmbH (OAT) of Germany, employing OAT’s bespoke silica resin design mix to provide innovative, cost-effective and time-efficient solutions to support Highways England, successfully completing a tight programme of slab lifting, stabilisation and bay replacement on the A180 — in a single weekend.
The challenge
Highways England’s Area 12 contains a number of heavily utilised sections of concrete road that are in need of enhanced maintenance, including both levelling as well as replacement of existing concrete slabs. One particular area requiring urgent attention was a section of the A180 between Grimsby and Barnetby Top.
Solution approach
A key driver for the success of this project was regular Early Contractor Involvement (ECI) meetings with the client and supply chain. These meetings allowed us to understand the opportunities as well as the constraints. With a complex site for each shift, all deliveries, roles and processes required careful coordination. When it came to deliveries, each contractor was allocated a specific time. Why? In addition to ensuring that the scheme ran smoothly and to schedule, doing this also — and most importantly — reduced the risk to the workforce from a large number of traffic movements.
The eastbound carriageway of the A180 was closed to traffic between Brocklesby and Barnet with a local diversion.ß
Facts & Figures
When?
March 5–7, 2021
Where?
21 linear metres of Maxicrete repairs on the A180
How?
Injecting resin into over
20,000 holes.
Technology
A two-component silicate resin, which cures to 90% full
strength within 15 minutes. Full compressive strength
of c.50n/mm2 is achieved within the hour.
Result
Slab lifting, stabilisation and bay replacement on the A180
Technology
Let’s start with a few facts about the resin product: an OAT Inject GEO-plus resin, it’s a two-component silicate resin that cures to 90% full strength within 15 minutes, and full compressive strength of 48n/mm2 is achieved within an hour. This method of grouting allows traffic to run on the newly lifted bays within 15 minutes.
As far as the concrete goes, it was provided by Spot On Concrete. Metrail specified Spot On Rapid, which is an innovative new design mix the company developed that achieves 33n/mm2 in 5 hours, 40n/mm2 in 12 hours and 50n/mm2 in 24 hours.
Execution
Phase 1 of the works: slab lifting.
Doing this required drilling through the concrete slab and injecting the highly specialised resin product under the slab, which raises the slab and then provides continuous support.
Phase 2 of the works:
replacing the adjacent bays that were too
badly damaged to be lifted.
In a separate activity Metrail carried out concrete repair work on a number of cracked slabs.
Result
Drawing on the knowledge of our skilled workforce and collaborating with A-one+, our partner OAT and our experienced supply chain, Metrail is pleased to report the successful completion of a tight programme of slab lifting, stabilisation and bay replacement on the A180. Our careful planning and use of lean tools and techniques was paramount to completing the scheme to a high standard that met Highways England’s imperatives — safety, quality and on-time delivery.
Impressions from the A180 Concrete Road Refurbishment
