Abandoned pipelines can create serious safety hazards and environmental problems. An abandoned pipe effectively creates an underground void, which can cause subsidence, soil destabilisation, and water ingress. This can increase the risk of residual fluids leaking into public areas and the ground collapsing.

In the interest of public safety and satisfying legal requirements, it is vital that councils and asset owners decommission abandoned pipelines and fill properly, quickly, and safely.

Terefil from Mainmark is a lightweight, engineered void fill solution for pipes of every size. Surpassing even the capabilities of cellular concrete or foam concrete, Terefil is a unique, specialist flowable fill material that can fill massive pipelines and concrete culverts quickly and cost-effectively.

Due to its pumpability and self-compacting properties, Terefil can fill entire abandoned pipes, leaving no unfilled spaces, air pockets or gaps. Unlike other fills and grouts, Terefil doesn’t release any water as it sets, ensuring zero bleed and minimal shrinkage along the crown of the pipe. The solution provides firm contact between the material and the pipe as it sets, preventing the formation of underground cavities or voids as the pipe degrades over time.

Terefil is a lightweight concrete or flowable grout that travels easily through a grouting pipe to fill voids of any size, including large abandoned pipes and culverts. This innovative flowable fill makes it easy to apply regardless of the size or length of the pipe or culvert. Importantly, it means pipes can be filled and decommissioned even when access is extremely limited. Pipes can be filled from a single entry point with the highly-flowable grout applied very quickly. 

Terefil is the lightweight polymer-modified cementitious fill of choice for mission-critical projects, ideal for when granular fills or aggregate material options are too heavy, site access is limited, or project schedules are tight.

Mainmark works fast to minimise downtime on site, with time spent on testing solutions and identifying the best formulation for the project before work begins.

Terefil can be used to void fill abandoned:

Fuel tanks

Concrete pipes

Concrete culverts



Underground tanks


Water mains




Wing walls.

We can decommission a variety of pipelines, culverts and tanks.



Density and strength can be matched to specific job requirements

A versatile and reliable solution that delivers engineered outcomes

Lightweight with a density as low as 320kg/m3

Reduces pressure on existing and surrounding infrastructure, including retaining walls, bridge approaches and slip planes

Can be placed at up to 70m3 an hour

A cost-effective solution for time-sensitive projects and tight schedules

Highly flowable and can be pumped more than 1,000 metres

Ideal for projects with site access issues

Achieves strengths of between 400 and 6,000 kPa (at 28 days)

Can withstand high loads, including large machinery and vehicular traffic, making it ideal for heavy traffic environments such as abandoned mines, runways and roads

Can stabilise soil without distributing or redirecting natural water flow

Hydraulic pressure and water courses are not compromised