Challenge
Concrete pavement slabs on the A55 had settled due to sub‑base voiding and loss of support, requiring rapid stabilisation without extended closures on this strategically important route.
Solution
Geobear used precision geopolymer injection to fill voids, improve bearing capacity and re‑level slabs during controlled traffic management, enabling rapid return to service.
High‑traffic A55 corridor
Defined slab treatment areas
Rapid curing after injection
The A55 is a key transport corridor supporting regional, commuter and freight traffic across North Wales. Sections of concrete pavement had experienced differential settlement caused by sub‑base washout and void formation beneath the slabs.
The resulting uneven surface affected ride quality and increased maintenance requirements. A technically robust stabilisation method was required to address the underlying loss of support while maintaining operational continuity on this high‑volume route.
Traditional break‑out and reconstruction would have required significant traffic management, extended closures and increased material use. Given the strategic importance of the A55, minimising disruption to road users was a primary requirement.
The intervention needed to stabilise the sub‑base, reinstate slab support and correct differential settlement within restricted working windows, while aligning with asset management and sustainability objectives.
Geobear designed a controlled geopolymer injection programme tailored to the affected slab sections. Small‑diameter holes were drilled through the concrete surface at predetermined centres.
The two‑component geopolymer was injected beneath the slabs, where it expanded to fill voids, bind loosened sub‑base material and increase bearing capacity. Controlled expansion enabled managed re‑levelling of the slabs, monitored in real time to ensure movement remained within specification tolerances.
Works were undertaken within planned traffic management windows. Due to the rapid strength gain of the geopolymer material, treated sections were returned to traffic shortly after completion, reducing programme duration and user impact.
The intervention restored slab support and corrected differential settlement without full excavation. Ride quality improved and the risk associated with further void development was mitigated.
Delivery within controlled working windows minimised disruption on this strategic route while providing a technically sound, low‑impact stabilisation solution consistent with long‑term asset performance objectives.
Get in touch with our expert team today and discover how Geobear can extend the life of your critical infrastructure assets.
