Most new bridges are built with a life expectancy of around 75 years, however, normal wear and tear cuts that lifespan by around 30 years. Bridge decks in particular deteriorate faster than any other part of the bridge due to direct impact from traffic, weather, and application of different chemicals (e.g., de-icing chemicals). The stressor of elements, chlorides, and brines attacks metals which cause the steel rebar to corrode, and as a result, the concrete may crack.
As such, selective demolition is often a requirement to reverse these effects, where hydrodemolition of bridge decks is often considered the best option.
The challenges of repairing bridge decks
Due to the vulnerability of deteriorating and structurally deficient bridges, selective demolition is often a requirement to restore them in a fast and cost-effective manner. Selective demolition is defined as the removal of damaged or low-strength concrete while leaving the health concrete intact.
However, construction repair (and especially selective removal) is anything but easy. It’s a strenuous and tedious process as maintaining its structure can be difficult. Bridge deck repairs will require that the old, damaged concrete be replaced without the removal of or risk of damaging the steel or beam structures. This can be achieved through various methods, most of which are unfortunately unsafe and don’t guarantee an easy extraction and replacement of the concrete. Mechanical methods such as jackhammers can potentially damage connectors or other embedded steel, while jackhammers, along with milling and hydraulic hammering, may also leave microfractures on the surface of the bridge deck concrete.
Instead, opting for hydrodemolition for bridge decks is often your best bet. It’s an efficient, cost-effective, and precise method to remove deteriorated concrete with high-pressure water without any risk of damaging the surrounding concrete or steel. It can be used for almost every part of the bridge, not just the bridge deck, including:
- Abutment walls
- Bearing foundations
- Piers (pillars)
- Parapet walls
Advantages of using hydrodemolition for bridge decks
Hydrodemolition of bridge decks remove concrete in a controlled manner without any vibrations which reduces the risk of microcracking. Many consider it the ideal concrete removal method, not only for bridges, due to its ability to create greater exposed aggregate areas which allows for great bonding with the new concrete or coating.
Hydrodemolition of bridge decks eases the concerns surrounding vulnerable bridges and the removal of damaged/structurally insufficient concrete through its many benefits:
- Noise and dust pollution are dramatically reduced
- The water can be collected for treatment and recyclable for future projects
- It’s cost- and time-effective
- Does not cause any microcracking, ensuring a long-lasting repair of high quality
- Allows for both selective and non-selective concrete removal
- Prepares an ideal surface for bonding between old and new concrete
- Keeps the rebar clean and intact, and removes existing corrosion
- Reduced risk of injury for operators
Conjet’s Automated Concrete Removal robots, utilizing the hydrodemolition technology, are the ideal choice if you are looking for a concrete bridge repair method that will maximize the bridge’s lifespan, increase workers’ safety and minimize traffic impacts. We call it ACR™.
For more information about hydrodemolition of bridge decks and what advantages hydrodemolition robots and frames provide in bridge restoration, contact Conjet.