Managing and rehabilitating underground infrastructure isn’t always the most glamorous business. But sometimes a particularly interesting project comes along that challenges you and the tried and true solutions you’ve always counted on – and it’s time to really think outside the box.
One of these interesting projects was a rehabilitation project installed in the middle of an extremely harsh Canadian winter.
Winnipeg-based MuddRuckers, Inc. braved truly ridiculous temperatures – in one of the worst winters in history – in order to complete their project for the Saskatchewan Department of Highways and Infrastructure. MuddRuckers utilized CentriPipe – a centrifugally cast concrete pipe (CCCP) lining system – to successfully bid and install the project. CCCP utilizes a high level of pressure, generated by a precisely controlled spincaster, to spray on multiple layers of fine aggregate composite concrete (FACC) inside the existing pipe, essentially creating a new concrete pipe within the old one. This new pipe attaches itself to the previous, failing substrate without having to rely on it for structural support.
For this particular project, a key aspect was flow capacity. With CentriPipe, the liner thickness is generally less than two inches thick, allowing for minimal flow reduction. This was a critical factor in securing the deal for MuddRuckers. General manager Doug Cook explains that "we were bidding against a sliplining proposal. But since sliplining would reduce capacity significantly, the contract called for a new push-through pipe run parallel to the existing pipe, to match original capacity."
The CCCP solution enabled MuddRuckers to bid considerably lower labor and resource costs over installation of a new parallel pipe, allowing them to submit their bid to the Saskatchewan Department of Highways and Infrastructure at a 25 percent lower cost than their closest competitor, saving the Department around $200,000 (CAD).
Once the bid was awarded, the real fun began! Controlling the work-site environment became the primary challenge. CentriPipe is a sprayed lining solution, requiring temperature control for effective curing. Due to the bone-chilling record low temperatures, MuddRuckers had to raise ground and culvert temperatures by 70 degrees Fahrenheit – (from below zero Fahrenheit, to around 68 degrees Fahrenheit), and maintain those temperatures as the lining cured. They managed to do this through an extensive procedure that Cook likened to a "military procedure." In order to heat up the culverts, 350,000 BTU heaters – known as "Herman Nelsons" – were brought to the sites, along with ground thaw heaters. Insulated panels were used to create small structures at the pipe openings to hold in the heat and allow crews to access the heated work sites. The project itself consisted of four large corrugated metal culverts of varying size, all on the verge of failure, with many pieces rusting and rotting. After some preparation work cleaning the pipes, the spin casting took place, with the CentriPipe spincaster being pulled through at calculated speeds. Each layer is a half-inch thick and can cure in a few hours, allowing multiple layers of Permacast PL-8000 to be applied within days.
CentriPipe provides an opportunity for a creative and effective solution to those of us working in infrastructure rehabilitation. It can achieve incredible results, under punishingly harsh conditions, at a lower cost than traditional alternatives.