Pipes and Culverts - Abandonment and Decommissioning
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 |
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Concrete pipes |
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Concrete culverts |
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Manholes |
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Tunnels |
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Underground tanks |
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Sewers |
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Water mains |
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Trenches |
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Mineshafts |
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Sinkholes |
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Wing walls. |
We can decommission a variety of pipelines, culverts and tanks.
Gas main pipes
When ageing or abandoned gas pipelines need to be safely decommissioned, they are often left in-situ to avoid the cost of substantial excavation to remove them, and the disruption this would cause to the local community. Mainmark can efficiently fill redundant gas pipes once they have been isolated from the broader gas network. Using Terefil, Mainmark’s advanced lightweight polymer-modified cementitious-based fill, works can be often be completed in one day, ensuring the pipe is structurally filled for maximum safety. Project timelines were reduced by 70 per cent when an ageing gas pipe in Melbourne was decommissioned using Terefil.
Water main pipes
The construction and placement of water main pipelines is important in ascertaining the potential risk of collapse and damage to the structures above ground. Disused pipelines below properties can lead to subsidence if the utility is compromised. To safely fill the pipelines, making them stable underground without the need for costly removal, Mainmark uses its unique Terefil lightweight cementitious fill which can be pumped from a single entry point. The solution has been recognised by many councils for its ability to deliver a fast, cost effective and long term solution for filling large voids and pipes. Terefil is commonly used to decommission water main lines that may lie beneath private properties, roads and other sensitive sites without the inconvenience of digging and disruption to the community. Mainmark successfully decommissioned a water main pipe that ran under several homes, roads and a school as part of the Hunter Water infrastructure upgrade project in New South Wales, using a single entry point for material placement.
Culverts
Whether due to structural damage, general dilapidation or redundancy, concrete culverts demand significant volumes of fill when being decommissioned. As a highly flowable and easily placed material, Terefil is ideal for this type of work. The solution does not require preloading or compaction for settlement mitigation, is applied both quickly and with controlled pressure, typically exhibiting shrinkage of less than 0.1% to 0.3%, subject to strength. Whatever the specification, Mainmark is able to devise the appropriate Terefil formulation to meet site specific requirements. This may include a design life of 100 years, a defined compressive strength to support above ground needs, and resistance to other substances, such as sulphates. Despite often limited site access, Mainmark is able to monitor fill progress and success in real time using sacrificial cameras installed within the crown of the culvert. This ensures the culvert has been completely filled, with no air pockets within the crown of the pipe.
Features |
Benefits |
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| Density and strength can be matched to specific job requirements | A versatile and reliable solution that delivers engineered outcomes |
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| Lightweight with a density as low as 320kg/m3 | Reduces pressure on existing and surrounding infrastructure, including retaining walls, bridge approaches and slip planes |
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| Can be placed at up to 70m3 an hour | A cost-effective solution for time-sensitive projects and tight schedules |
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| Highly flowable and can be pumped more than 1,000 metres | Ideal for projects with site access issues |
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| 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 |
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| Can stabilise soil without distributing or redirecting natural water flow | Hydraulic pressure and water courses are not compromised |
