Northumberland Avenue in Reading is a busy strategic route to schools, residential and commercial properties, but through years of damage to the concrete slab and the increased heavy vehicle use the surface of the road was saturated in fretting and potholes – so Reading Borough Council put plans in place to make the necessary repairs.
The concrete slab had been badly damaged by utility trenches and ducting that had been installed within the road over the last two decades and due to the unfavourable ground conditions, there was differential settlement of the slabs. This resulted in cracking and pot holes reflecting through the slab to the surfacing course. The council were committed to preventing these problems rather than treatment, so wanted a longer term solution without the need to reconstruct the road at considerable delay and cost on a strategic route.
The council approached Geobear to look at viability of treating the ground beneath the concrete. Firstly, in order to fully understand the extent of the issue a GPR survey was completed to analyse the composition of the ground. The results highlighted significant voiding and a soft base layer, meaning throughout a 400 metre stretch of road the integrity of the concrete slabs was being compromised by weak ground.
The weakened ground had to be stabilised or a resurface would suffer similar accelerated deterioration; as the ground moves the concrete base also moves meaning the asphalt surface is more prone to distress.
Geobear drilled through the road and subsurface to inject geopolymer resins that expand to fill voids and mix with the existing elements to harden forming a solid base under the concrete.
The procedure for the work was to drill at measured intersections into the road and inject a formula of expansive resin into the ground beneath the concrete at depths of 1 metre and 3 metres. Different resin compositions are used depending on soil condition and vary in terms of expansive force and the time it takes to harden.
The technical teams on site use laser monitoring to observe fine movement in the ground level and once a movement limit is reached the resin is injected at the next interval.
The stretch of road in Reading took the Geobear project team two weeks to complete. and a contractor was subsequently employed to resurface the treated sections.
Reading Borough Council was pleased with the outcome highlghitng that when you consider the economics, they are accruing long term savings by investing in the future of roads. Their strategy is to consider all the options available and ensure our programme of work delivers the best possible outcome to the local community.
Geobear has worked with the council on a number of schemes and our methods have consistently worked. Sam Shean, Streetcare Manager at Reading Borough Council was pleased with the results stating, “We’ve worked with Geobear on a number of schemes and their methods always deliver for us”.