Roads and transport infrastructure

Subsidence can cause major disruption to roads resulting in fractures on the road itself, unevenness, and sinkholes.

Movement in the concrete base

The deterioration of the road surface is usually due to the concrete base underneath the asphalt experiencing movement. Changes in the soil and its ability to support the concrete and asphalt structure of the road above can mean that concrete slabs subside, causing bumps cracks and other issues with the road surface.

There are several different reasons why the subsoil may become unstable or form voids e.g.

  • Cohesive soils
  • Washout
  • Rainwater ingress
  • Burrowed animals
  • Traffic vibration
  • Poor drainage

If the subsoil underneath the road is a cohesive soil, such as clay or silt, it is prone to swelling and shrinkage as seasonal changes approach. The above soil tends to hold moisture, meaning that during periods of heavy rainfall the soil will swell and become larger. Accordingly, during hot weather, water is drained from the soil, and it contracts. It is in this situation that the contracting soil can cause concrete slabs on the highway to subside

Poor drainage and washout is another common issue, Washout tends to affect sand and gravel-based soil which is easily washed away with an influx of water.

Sunken and uneven roads can be unsafe to travel on and could cause serious harm to yourself and/or other road users.

Hereat at Rectify we raise and re-support sunken and uneven roads, railway lines, and infrastructure. In most cases, the work can be carried out around vehicles and train traffic without disturbance.


There are typically several alternatives to rectify this issue. 

A common way is digging out and replacing the section of road. If it’s a slab issue it could be lifted and replaced, deep recycling could be used whereby existing materials are re-used in-situ. Another alternative could be to patch only the worst sections or areas that needs patching, all these solutions can be a lengthy process with great expense involved.

With our solution, we use a specialised polyurethane resin that fills any voids underneath the slab/road. The resin injection process takes place through a 16mm diameter tube, this process is non-invasive its quick, strong, and backed by a 10-year workmanship warranty. Our polyurethane resin is environmentally friendly and sets within a couple of minutes and is fully cured in 15mins. which means traffic can flow through a treatment area soon after the injection work has been completed. At Rectify we repair and relevel any type of road construction raging from Major freeways, residential or commercial roads, tunnel junctions, weighbridges, level crossings and more.

Road solving problems

  • Backfill service trenches and retaining walls
  • Spray foam for pipeline trench breakers and pipe supports
  • Replace unstable soils, and fill large voids with our lightweight polyurethane resin

Filling decommissioned tunnels and sinkholes with our lightweight resin

Relevel and restabilise uneven concrete roads, driveways, and slabs

Stabilise and void fill bridge pillars

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