Contractors know hydrodemolition projects come in all shapes and sizes. Some jobsites provide a decent amount of workspace in more open areas, allowing contractors to utilize larger equipment. Other projects take place in confined spaces, such as building interiors, that limit the size of equipment.
For these applications, contractors require a machine that still provides adequate power but has the compactness to go where larger equipment is unable to access.
Tight spaces are where the Aquajet Ergo shines. Its compact size allows it to work in cramped spaces while delivering four times more power than a hand lance. Its remote-control functionality also increases safety, allowing the operator to work out of harm’s way. With its safety and versatility offerings, the Ergo is ideal for contractors with close-quarter projects.
Limited access
A unique project occurred in the basement of an industrial building in Montreal. The building required a new layout for tanks, each of which requiring a drain line. The contractor tasked with the job needed to create trenches in the basement’s concrete to install the new drainpipes.
The building owner didn’t want jackhammers or saws to be used because they wanted to keep the rebar intact. The concrete slab couldn’t be damaged because of water pressure from the ground water under the building. Furthermore, the basement setting offered limited access that restricted larger equipment from entering.
Montreal-based Groupe MGC took on the project. Groupe MGC purchased an Aquajet Ergo in summer 2021 that was the ideal machine to tackle the job.
“Based on the space we had to work in, the compactness of the Ergo was an advantage,” said Carl Henri, Groupe MGC President said.
“We could have used larger equipment in the work area itself, but limited access made it impossible to get the equipment into the building. One of the main reasons we invested in the Ergo is for projects that require us to work in tighter spaces where we can’t bring larger machines.”
The crew removed 20 cubic metres of concrete at a depth of about 60 cm for the challenging project. Groupe MGC completed the job in about 22 days using a crew of four to six people. Handling wastewater was particularly challenging given the location of the job, where only compact equipment could access the work area. The crew collected water and debris from the work zone with a vacuum truck and transferred it to a holding tank for treatment.
Subzero hydrodemolition
During the winter in northern Alberta, a pulp and paper plant removed a pump from a below-grade chamber for maintenance. After pulling the pump, they discovered the surrounding concrete was deteriorated to the point of having exposed rebar. The concrete walls were about 30-cm thick with about 10 cm of the concrete chewed away. The ceiling was in a similar state.
The plant engineer worked with the Edmonton-based Restocrete, Inc. in the past and was impressed with their execution of a previous contract. Restocrete managers Nick and Justin Downar needed an efficient hydrodemolition machine that could be operated from a safe distance above the chamber, so they turned to the Aquajet Ergo.
“Once we decided to make the jump and invest in the equipment, we saw the ROI. The equipment was smooth and the relationship with Aquajet has been great,” Nick Downar, Restocrete’s General Manager said.
“It requires less workers, gets rid of silica dust, keeps time off tools reducing opportunities for injuries and has been easy to take care of. The Ergo also allowed Restocrete to remove deteriorated concrete without vibrating the existing structure, which was mandated by the client. It was a big win for us.”
The environment presented multiple challenges, beginning with the area for removal. The pit with the damaged concrete was below the water table and a confined space at about 4.9 metres deep, making traditional removal methods difficult and potentially dangerous. However, thanks to the Ergo’s remote-control capabilities, the Restocrete crew could operate the equipment safely from above, with significant reduction of time in the pit for removal.
The weather presented another hurdle. Temperatures during the project dropped as low as -30 C. The Restocrete crew constructed insulated hoarding for the Ergo and Jetstream pump with heaters running throughout the project. The tent provided some protection from the elements but couldn’t be entirely sealed, allowing a freezing wind to flow through at times.
Visibility also became an issue as the temperature difference between the air in the pit and inside of hoarding produced a great deal of steam when 40,000 psi was used. This hindered visibility and forced the crew to halt work at various points to let the air clear and ensure operation in the pit was running smoothly.
At project end, Restocrete completed concrete removal and repair on three of the five chambers at the plant, taking out all deteriorated concrete, extending behind the rebar, at a depth of up to 15 cm. The hydrodemolition portion took about a week. Then, they had to go back, form and pump the concrete, then coat it.
“Even with the timeline slightly drawn out due to pausing at points because of the steam, this project was significantly faster, leaving better quality surface profile and overall concrete condition with Hydrodemolition than what it would’ve been with jackhammering,” said Justin Downar, Restocrete’s Commercial Manager.
Whether it’s an industrial building or an underground pit, using an Ergo for hydrodemolition provides an efficient, versatile solution for contractors.
The heightened safety, remote-control operation in confined spaces and efficiency has made it an appealing replacement for traditional concrete removal and repair methods.
