Pumpable, lightweight cementitious fill — pipeline abandonment, void stabilisation, and abutment backfill.
Foamed concrete is produced by combining a cementitious slurry with a pre-formed foam to create a self-compacting, pumpable fill material with densities from 400 to 1,600 kg/m³. The low density is adjustable to suit the load and lateral pressure requirements of each application, and the cementitious composition provides long-term durability with resistance to groundwater and biological attack. Because it is pumpable and self-compacting, foamed concrete can fill complex shapes, long pipe runs, and inaccessible voids without vibration, compaction, or excavation.
It can be pumped over 200 m through small-diameter pipes, reaching locations inaccessible to conventional placing equipment. Filling a decommissioned pipeline or culvert by pumping foamed concrete through existing access points avoids the cost and disruption of excavating to the structure, which on live road corridors can be the dominant project cost. Initial set typically occurs within 4–6 hours, allowing traffic loading to be restored on the same or following day. All foamed concrete works are designed and supervised by our in-house engineering team.
APPLICATIONS
GSI NZ CAPABILITY
THE GSI DIFFERENCE
Step 1
We assess the void volume, geometry, and loading requirements. Mix design determines the target density and strength, with the binder and foam dosage calibrated to achieve the required performance for the specific application.
Step 2
Foamed concrete is produced on-site and pumped through appropriately sized pipework to the placement location. Flow rates and pipe routing are planned to ensure consistent fill quality over long pump distances and in complex geometries.
Step 3
Initial set typically occurs within 4–6 hours, allowing rapid restoration of traffic or site access. Density cubes are taken during production for QA testing. A completion report with mix records and test results is provided on handover.
CAPABILITY
New Zealand's aging infrastructure network includes thousands of redundant pipelines, decommissioned culverts, and voided bridge abutments, all of which present ongoing subsidence and structural risk unless properly treated. Foamed concrete provides a fast, durable, and cost-effective solution that avoids the disruption of excavation on live corridors.
GSI NZ has deployed foamed concrete across multiple transport and infrastructure projects in New Zealand, including pipeline abandonment on live state highway corridors where excavation to the asset was not viable, and abutment backfill where reducing lateral earth pressure was a design requirement. The same team delivers mix design, production, and placement under one contract.
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Lightweight, flowable, and controllable — foamed concrete is ideal for void filling, annulus grouting, and applications where weight matters. Ask our engineers if it's right for your project.
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