Hydrodemolition Archives

Hydrodemolition 101 – terminology

April 19, 2022/in Blog post, Hydrodemolition /by Rebecca nilsson

If you are new to the the world of hydrodemolition the terminology can sometimes be difficult. This is a list of specific terms being used in the concrete removal and hydrodemolition field.

ACR™

Automated Concrete Removal. Selective or non-selective removal of concrete from structures done by hydrodemolition robots being programmed and remotely operated.

BAR (UNIT)

A metric unit of pressure. 1 Bar = 14.5 psi

1 = atmospheric pressure at an altitude of 111 meters above sea level at 15 deg. C.

BONDING

When new concrete is put on top of old concrete, to restore a structure.

COMPRESSIVE STRENGTH

The ability of concrete to withstand forces that are pushing on it without braking.

CRADLE

The assembly that the cutting lance is attached to and allows the robot to aim and manipulate the water jet.

CUTTING LANCE

The assemble including the nozzle that is the robots final contact with the water.

FEED BEAM

The structure of the robot that the cradle travel on. It can be straight or curved to match a surface profile.

HYDRODEMOLITION

The process of selective removal of concrete by means of one or more high-speed water jets. You can read more about hydrodemolition here.

MICRO-CRACK

A crack in the structure that appears when concrete is removed using methods creating friction in the structures, which in turn creates micro cracks.

MPA

Multipurpose arm. This is one of Conjets unique features and it allows you to easily adjust and position the cutting head from the remote control.

NALTA

The smallest ACR™ robot on the market, allowing allows selective concrete removal in inaccessible areas.

NON-SELECTIVE REMOVAL

The capacity to remove concrete to a specific depth, not based on the concrete strength.

MPA (MEGAPASCAL)

A unit for measuring pressure or stress

1 MPa = 145.038 psi

PSI (POUNDS PER SQUARE INCH)

A unit for measuring pressure or stress.

14.7 psi = atmospheric pressure sea level

SELECTIVE REMOVAL

The capacity to remove concrete by its strength and not to a specified depth.

STEP LENGTH

The distance the track(s) will move during operation.

STEP SPEED

Determines the length of time the valve for track movement is open during operation.

STRUCTURES

Different constructions build of concrete: bridges, dams, docks, parking decks, tunnels etc.

TENSILE STRENGTH

The ability of the concrete to withstand pulling forces without breaking.

Why you should use robotic technology to remove concrete

April 11, 2022/in Blog post, Hydrodemolition /by Rebecca nilsson

Swedish-based Conjet has spent more than 35 years on innovation and engineering around Automated Concrete Removal – ACR™ using hydrodemolition. Conjets mission has always been to develop a solution that removes concrete for restoration of structures in a safe manner, where no micro-cracks are created, leaving a surface ideal for bonding. The soultion is called ACR™ – Automated Concrete Removal.

Automated Concrete Removal (ACR™) is a method utilizing robotic technology to remove concrete from building structures such as bridges, parking decks, dams and tunnels, using high pressure water – hydrodemolition.

Hydrodemolition technology ensures that no micro-cracks are created during the concrete removal process and provides an ideal surface for bonding of new concrete, while the robot secures the quality and consistency of the removal process.

Using ACR™ fully automates the operation of concrete removal, allowing you to provide a safe working environment and increase production efficiency. In just one day, a single Conjet ACR™ robot removes the same amount of concrete as up to 25 operators with jackhammers. Even better, the ACR™ robot significantly limits the noise and eliminates dust and vibrations caused by conventional jackhammer methods.

KEY BENEFITS WITH AUTOMATED CONCRETE REMOVAL (ACR™)

Safe. All operations can be controlled from the ONE system wireless control, leaving the operator out of harm’s way.
Reliable. 35+ years of innovation and engineering has resulted in solid knowledge and experience of successful concrete removal on hundreds of structures.
Automation. The Conjet ONE control system allows operators to easily set removal parameters.
Sustainable. With selective removal, only damaged concrete is removed, without leaving micro-cracks.
Allows for either selective and non-selective removal. From scarification to deep removals and even through slab.
Ease of use. State of the art GUI and reliable components.
Versatility. Repositioning for another type of work is done in minutes. From the reach and stability of the robot to the available accessories ACR has you covered.
Cloud connectivity. Always connected to the cloud. The operator can have both the robot and powerpack at his or her fingertips.

THIS IS HOW ACR™ WORKS

After completing the start-up routine, the operator can load a saved set of parameters or enter new parameters on the ACR™ robot, either directly on the robot’s display or using the handheld remote control. The operator then positions the robot and starts the automated concrete removal process from a safe distance of 15-30 feet (5-10 meters).

The robot then operates autonomously according to the chosen parameters, working its way in a straight line, in a curve, or in a circle, while the operator monitors and supervises the process.

WHY AUTOMATED CONCRETE REMOVAL – ACR™

WORK AND HEALTH SAFETY

The biggest challenge on all sites where concrete is being removed, or even demolished, is to secure work and health safety for the operators.

Using ACR™ hydrodemolition robots to get the job done is a way to secure a safe working environment for the operators.

RELIABLE

As with all automated solutions, the ACR™ robot is programmed to do the job according to specification. Whether it is to remove the concrete down to a certain depth or quality, the ACR™ robot will prepare a surface optimized for bonding.

SUSTAINABLE

The preferred method for ACR™ robots is to remove concrete using a high-pressure water jet – or hydrodemolition.

This is a sustainable way to remove the concrete from any structure where no micro-cracks are created, and therefore the remaining structure does not need further inspection or analysis. It extends the useful life of the structure. Eliminates vibrations and dust; dramatically reduces noise.

EASE OF USE

Once properly trained, the operator will find the ACR™ robots easy to use with built-in operator guides, instructions, and visual feedback on the settings.

FLEXIBLE

ACR™ robots are engineered to get the job done, no matter if the surface is horizontal, vertical, cylinder shaped – or all of the above. The time it takes to re-program the robot is minimal, and with a wide variety of accessories available, you can get any job done using the same robot without the need for rebuilding.

CONNECTIVITY

The ACR™ robots are connected to the cloud. Conjet Connect allows you to monitor real time data, store data and can over time support you in optimizing your fleet’s efficiency.

SAFETY FIRST! – ACR™ AND SAFETY

One of the biggest challenges on all sites where concrete is being removed, or even demolished, is to ensure the health and safety of the workers.

Using ACR™ robots to get the job done is a way to keep a safe working environment for the workers. The robots are operated via the Conjet ONE control system, allowing all operations to be configured and monitored from the radio remote control box at a safe distance from the robot.

CONJET ONE FOR SAFE, AUTOMATED OPERATIONS

The ACR™ robots can be configured from the display on the robot itself, or from a distance using the user-friendly radio-remote control box. This results in shorter start-up time and increased operational efficiency.

The Conjet ONE controls not only the robot, but it communicates with the high-pressure pump.

Even if the ACR™ robots allow for fully automated operations, the robot requires reactivation from the operator in a set time interval to continue the job. Failure to do so will bring the high-pressure pump to idle position, which in turn stops the robot. The reactivation is easily done from a distance by touching the hand-held control-unit.

CHECKLISTS

Every ACR™ robot is delivered with a daily checklist on items that should be signed off on by the operator before starting the shift.

By using the checklist, the on-site safety officer or supervisor can ensure that work safety regulations are being followed with regards to the robot, as well as maintaining minimum downtime and sufficient maintenance of the robot.

NOISE AND VIBRATIONS

The ACR™ robots are built around hydrodemolition technology, using high-pressure water to remove the concrete. This technology is much quieter than traditional concrete removal and demolition technologies. It doesn’t create any vibrations, and therefore improves the overall working site environment. Traditional jackhammers cause vibrations in the structure and that disturbs others on multiple floors.

This makes ACR™ the optimal solution for sites located in a building with residences and/or offices.

SAFE FOR THE STRUCTURE

Hydrodemolition technology is the preferred technology for restoration of concrete structures as it creates zero vibrations and zero micro-cracks. Moreover, the surface left after removal is ideal for bonding. This results in a longer structure life after repair, which in turn gives a better return of investment for the owner.

OPTIMIZED UPTIME AND PRECISION – ACR™ AND RELIABILITY

Once the job is defined, and you have been awarded the contract to do the project, the real challenge begins. How do you ensure the job is done in a safe way, within the agreed timeframe and budget?

MINIMIZED DOWN TIME

If ACR™ is the chosen method for restoration, downtime is automatically minimized. The robots used are very reliable, which means minimal unplanned downtime due to breakdowns.

The ACR robot is highly efficient thanks its multipurpose design, as the time it takes to shift from one surface to another (horizontal to vertical) is done by the operator using a handheld remote control. So, both planned downtime and unplanned downtime are greatly reduced.

PRECISION

ACR™ uses hydrodemolition as the method to remove concrete. This allows the owner of the structure – and in the end the operator monitoring the robot doing the work – to choose between selective and non-selective removal. Selective removal means that the ACR™-robot is configured to remove the concrete of a certain quality or compressive strength (measured in MPa or psi), whereas non-selective removal means removing a certain depth of the concrete surface. No matter which option is preferred, the ACR™ robots will deliver the required results leaving a surface ideal for bonding.

SERVICE & SPARE PARTS AVAILABILITY

Conjet, the provider of ACR™ robots, has a global network of certified partners and distributors, ensuring that your robot is well taken care of and that downtime is kept to a minimum.

CERTIFY YOUR OPERATORS

To optimize the uptime for the ACR™ robots, it is also advised to certify operators with Conjet University. The operators will not only be trained on how to configure the robot to get the desired results, he/she will also be trained on the safety routines required at the beginning of every shift as well as preventative maintenance, troubleshooting and replacement of consumables.

DATA ANALYSIS

The ACR™ robots are all prepared with Conjet Connect – a feature that collects data on the operations being performed. By analyzing this data, you can get in-depth knowledge on robot performance. This knowledge can be used to optimize your stock of consumables, plan services and in the end, lead to increased uptime.

SUSTAINABLE CONCRETE REMOVAL FOR BRIDGES

April 6, 2022/in Blog post, Hydrodemolition /by Rebecca nilsson

Bridges are an important part of infrastructure – an enabler for urbanization and efficient movement of people in daily life. Bridges are by default very exposed to weather and wind thanks to their surrounding environment. Hydrodemolition is the right method to get the concrete bridge repair job done most effectively – here we tell you why!

The history of bridges started in ancient times, and ever since then architects and engineers have improved them to the point they are today – mighty structures that span mountains, lakes and oceans. The Romans revolutionized the building technique by introducing arches, resulting in a structure that was very rigid and strong. The Turkish Karamagara Bridge that was built in the 5th or 6th century represents the oldest surviving Roman bridge that features pointed arch.

Many historical battles have been fought over the control of these bridges, making them a symbol of control of the flow of people and goods across rivers and canyons. Today, bridges are an important part of infrastructure – an enabler for urbanization and efficient movement of people in daily life.

Golden Gate Bridge, US

No one really knows how many bridges there are on planet earth, but the fact that there were over 600,000 bridges in the US alone in 2016 tells us something about the great number.

Out of these, 4 out of 10 – or 240,000 – are older than 50 years. It is estimated that 188 million trips annually are done over bridges that are structurally deficient, and recent estimates puts the investment needed for bridge rehabilitation in the US alone to a $123 billion.

In Europe, the situation is the same. In Italy, 300 bridges are at risk for failure and in Sweden, 800 out of a total 21,000 bridges are being investigated for needs of repair. Out of France’s 12,000 bridges one-third are in urgent need of repair and in Germany 1 out of 10 of the country’s 39,000 bridges are in bad condition.

Uddevalla bridge, Sweden

AGEING AND OTHER CHALLENGES WHEN RESTORING A BRIDGE

Bridges are by default very exposed to weather and wind thanks to their surrounding environment. Additional causes of aging over time are in general:

Chloride penetration. Chloride (salt) is often spread on roads and bridges in order to prevent ice from being created on road surfaces. On structures close to water, the salt is brought by wind or permeated in through cracks directly from the ocean. Once inside, the chloride causes corrosion at the rebars. The rebars expand when they corrode and, consequently, crack the surrounding concrete. These damages lead to an increased penetration of water and chloride, which speed up the aging procedure.
Freeze-thaw cycles. A similar cracking procedure of the concrete occurrs when water and moist inside the concrete freezes and thereby expands. The concrete can only withstand a specific amount of freezing cycles. This means that a concrete structure e.g. a bridge in an area where the temperature fluctuates around the freezing point will age a lot faster than one in a less seasonal climate.
Concrete is naturally basic but in contact with the air a chemical reaction caused by the carbon dioxide (Co2) decreases the pH value. When it gets too low (pH < 9) the corrosion of the reinforcement will accelerate (compared to the chloride penetration mentioned above). When this phenomenon occurs the carbonated concrete must be replaced.

Other challenges when restoring a bridge:

Abutment walls can be located on cliff faces and inaccessible to some equipment.
Beams can be at great heights above the ground or over water with nowhere to station a robot underneath.
Bearing foundations have limited access for a conventional hydrodemolition robot.
Decks with today’s high volumes of traffic the schedules are tighter than ever before.
Piers (Pillars): being the foundation of the bridge they can be of great height and are sometimes located partially under water or in the medians of other roadways or shipping channels.
Parapet walls: located along the edges of the bridge these are most exposed to the elements but are vulnerable to impact and even fire damage caused by vehicle accidents.

SUSTAINABLE RESULTS!

The keys to a sustainable, long-lasting result when restoring a bridge are:

Create a surface that is ideal for bonding new concrete.
Ensure that no micro-cracks are created in the process of removing damaged and/or old concrete.
Ensure that no damage is caused to the re-bars when removing the damaged and/or old concrete.
Use a methodology allowing the choice of selective (removal of the concrete down to a specific quality/strength) or non-selective removal (removal of x, y or z metrics of concrete, no matter the quality.

The aging of concrete is not linear, so hydrodemolition is the right method to get the bridge repair job done most effectively. The ACR™ robots have been developed to allow both selective and non-selective removal, leaving no micro-cracks or damage to the re-bars in the structure and a surface ideal for bonding.

THIS IS HOW ACR™ AND HYDRODEMOLITION HELPS:

Abutment walls: If the robot arm does not allow you to reach the removal area a tower attachment or a frame system are available.
Beams: the integrated arm of the robot allows you to remove the slab with the robot positioned on a solid area.
Bearing foundations: if there is not enough room for the robot, a frame system can get the job done.
Decks: with today’s high volumes of traffic the schedules are tighter than ever before. The arc robot with One control allows for ease of operation and less downtime, helping you keep on schedule.
Piers (Pillars): A frame system can be setup on the pier, and you can accomplish the removals either in stages or with a larger frame to cover the entire area in one setup.
Parapet walls: not only can you extend the tracks but also slide the body of the robot for extra stability, when reaching over the wall. All without any additional attachments.

Want to know how Conjet’s hydrodemolition robots can make you concrete brigde repair more efficient? Contact us here!

Advantages of using hydrodemolition for concrete preparation

March 22, 2022/in Blog post, Hydrodemolition /by SEO GO MO

One of the most important aspects of a successful concrete repair project is the quality of the concrete surface preparation. In the end, most concrete repairs fail due to poor concrete surface preparation. All unsound concrete must be removed to create a rough, clean, irregular profile that is completely free from micro-fractures to ensure that the new concrete will bond properly.

Hydrodemolition has proven itself to be one of the most effective methods for concrete preparation to create the ideal surface for bonding. So, how does hydrodemolition work and what advantages does it entail?

Surface preparation with hydrodemolition

When removing concrete using hydrodemolition, the cement matrix is removed from the aggregate, leaving bulk debris of sand and aggregate to be collected and disposed of. Once the debris has been removed from the hydrodemolished surface, some detail chipping may at times be required to remove any stubborn concrete that remains.

To complete the concrete preparation, final cleaning is often necessary to clean the surface of any bulk debris or slurry that could inhibit a good bond with the new concrete. Afterwards, any standing water needs to be removed before the concrete surface will be ready to accept a new overlay or patch material. Remember that sandblasting of the rebar is not required since the hydrodemolition process completely cleans all the exposed reinforcing steel.

Advantages of hydrodemolition concrete preparation and removal

Hydrodemolition presents numerous advantages when it comes to concrete preparation and removal including:

Does not cause any micro-cracks in the remaining structure, thus ensuring the repair will be long-lasting and of high-quality.
Allows for both selective and non-selective removal of concrete and other materials.
Creates no vibrations and dramatically reduces the amount of noise and dust during the removal process.
Keeps the rebars clean and intact, sparing you the time and effort of sandblasting the reinforcing steel.
A Conjet hydrodemolition robot is ~25x faster than mechanical jackhammering.
Prepares a surface ideal for bonding between old and new concrete with a rough, clean, irregular profile.

As in the case of any concrete restoration project, proper planning and execution is key to a successful outcome. In conclusion, the quality of a hydrodemolished surface can be far better for bonding with new concrete than a surface prepared using traditional methods such as concrete breakers. The same benefits of hydrodemolition for concrete preparation can be achieved regardless of whether the concrete removal is on a horizontal, vertical, or overhead surface.

Read more about the advantages of using hydrodemolition equipment for concrete preparation.

Achieve high-quality concrete preparation enabled by hydrodemolition with Conjet

Experience efficient, cost-effective, and sustainable concrete preparation using the Conjet ACR™ robots. They offer advanced surface solutions to quickly and safely remove coatings, rust, and other tough adherents. The surface preparation technologies we provide gives you the same productivity without the expense, hazards, and accompanying clean-up problems of traditional methods.