Page 73 - Occupational Health & Safety, July/August 2019

effectiveness of its high-pressure jets. Innovative technology ad- justs and maintains the distance from the nozzle to the point of impact, as well as the nozzle’s angle, movement, and water exit speed. The computerized controls also allow consistent results im- possible to achieve with a hand lance. Additionally, hydrodemoli- tion robots’ compact nature allows them to reach tight, confined spaces. Various design features and additional attachments also allow for work on any vertical, curved, or horizontal surface. This greatly increases productivity and reduces the number of tools needed on a job site.
Reduced Impacts
Sound, vibrations, lane closures, and project timelines are all fac- tors to consider when selecting the best approach for a bridge re- pair job. While a crew of 10 laborers might get the job completed, it’s noisy, disruptive, and may impact working hours.
Hydrodemolition offers a quieter solution. Hydrodemolition robots generally produce less noise than a hand-held pneumatic tool, and the sound is limited by the machine’s hood. The re- duced noise allows contractors to work in residential areas or avoid busy travel times by working during hours when noise levels are restricted.
In addition to the robot, a complete hydrodemolition system should include a high-pressure power pack and, potentially, a water
treatment system to handle the slurry, depending on local regu- lations. Contractors can pair the robots with self-contained water treatment units that can handle up to 5,000 gallons per hour. The 20-foot units discharge clean water back into the environment after reducing pH values to 7 and turbidity levels to just 25 ppm. Crews commonly use a trash pump to recover used water and return it to the water treatment unit. A vac-truck can also be used to transport wastewater off site.
Growing Demand
This unique approach to concrete removal will only become more popular. The innovative method is one of contractors’ best tools for the efficient, cost-effective, and precise removal of concrete from a variety of structures. It represents one piece of the puzzle in restor- ing structural integrity to the thousands of bridges in dire need of repair.
Peter Bigwood is the vice president of sales and marketing for Aqua- jet’s North American subsidiary and for Brokk, Inc., a manufacturer of remote-controlled demolition robots. He has more than 30 years of industry and leadership experience. Bigwood is on the boards of the National Demolition Association and the Concrete Sawing and Drilling Association. He also is on the safety committee for the Steel Manufacturers Association.
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