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Automated system detects and fills cracks in asphalt roads

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June 23, 2012

GTRI's prototype automatic pavement crack detection and repair system

GTRI's prototype automatic pavement crack detection and repair system

Image Gallery (2 images)

They say an ounce of prevention is worth a pound of cure, but when it comes to road maintenance, an ounce of prevention is worth several tons of tarmac. A tiny crack in the asphalt may not seem like much, but once it lets in rain and frost, it’s a ticket to potholes and a very expensive resurfacing. The problem is that crack repair is time consuming and labor intensive, so the Georgia Tech Research Institute (GTRI) has come up with an automatic pavement crack detection and repair system that operates at comparable speeds to conventional methods, but with fewer people and less exposure to hazardous fumes.

Road resurfacing, which involves tearing up old tarmac, repairing roadbeds and laying down a new surface is expensive, time-consuming, labor intensive and can be a massive disruption for motorists. Because of this, regular maintenance to deal with roadway cracks is vital to keep traffic flowing smoothly and roadwork costs down. Unfortunately, conventional methods for dealing with cracks also require a relatively large crew and the work is boring, repetitive and exposes workers to hazardous fumes. For this reason, a Georgia Tech team led by GTRI research engineer Jonathan Holmes are developing an automated system that identifies, maps and repairs road cracks on its own.

Currently, the scope of the project is limited to dealing with thin cracks that require only simple repairs rather than the larger ones that indicate roadbed damage and need more extensive work. This approach makes the development task manageable because the repair of thin cracks only requires the application of a liquid sealing compound.

LED imaging system

Unlike conventional methods, the Georgia Tech system needs only one operator. Since the only thing the operator does is guide the machine down the road, this is not only a major savings, but the operator is also safe from toxic fumes given off by the sealant.

The machine manages this by means of a stereoscopic imaging system that automatically identifies and maps the cracks. The system uses two sets of LEDs aligned parallel and perpendicular to the road surface. Each LED set is in a different color and a stereo camera takes two images. Based on the contrasting information produced by these two colors, a thresholding and filtering algorithm generates within 100 milliseconds a map of any cracks as small as an eighth of an inch (3 mm) in width. This map is used by the machine to guide an array of twelve nozzles that efficiently spray sealant into the cracks. The whole system can operate at a speed of up to 3 mph (4.8 km/h)

Example of a crack repaired by the GTRI system

The Georgia Tech system is still in the proof of concept stage of development. “Our prototype system has proved in many ways that a commercial-scale automated crack sealing system is viable, said Holmes. "We demonstrated solutions to technical challenges - including the high-speed firing of nozzles, automated crack detection and navigation - in a real-time, limited-scale system.” The imaging system is still in need of improvement with only an 83 percent success rate for mapping and the imaging algorithm is in need of tweaking. Holmes also believes that the sealant supply system could be improved.

Currently, the machine can only operate on a narrow strip of highway, but it was designed to be modular, so building a larger version that can handle an entire lane or road at a time is a simple matter of scaling up. If this is possible, then the device could have great potential if it can be extended to handle more aspects of crack mending. Repairing cracks, especially larger ones that may contain debris and dealing with complicated “alligator” cracking is more than just squirting sealant. If the Georgia Tech system can be built deal with general crack repair, then at least one road maintenance job will be in future reduced to the same level of motorist aggravation as the passing of a street sweeper.

Source: GTRI

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past.   All articles by David Szondy
9 Comments

There is still going to be disruption of traffic with a 3 MPH speed. Also, how long does it take for the sealant to cure? If it needs to cure for an appreciable amount of time, this not only involves lane closure (traffic disruption) but also more man power than stated since someone would need to cone off a section of road.

Rt1583
24th June, 2012 @ 08:16 pm PDT

@Rt1583 - if you're only going at 3mph, you're going to have to cone off a lane anyway. I guess the thought is just that this will require less manpower (and possibly be more efficient), hence make pothole prevention look more economically attractive. As the author notes, though, this would only work if the machine were a lot more flexible in its capabilities than it is now. So I'd say this was a long way off.

Will McNeill
25th June, 2012 @ 02:58 am PDT

Is that meant to be a repair? Seriously? Ive seen better overbanding by a bloke walking along with a kettle of hot tar. An as a motorcyclist I just see this kind of repair as a slip risk

ihateorange
25th June, 2012 @ 03:59 am PDT

While some other people can provide nothing but hate and naysaying- I think that for an emerging technology this is pretty awesome and it's time has come. Sure Rt1583, Will McNeill and ihateorange can crap all over the idea- the truth is that whenever a fix to a problem is suggested, it's immediately trashed upon by those who aren't fixiing it anyways- or perhaps you are all a bunch of road workers temping at LaborReady, worried you'll lose your jobs? Well I, for one am a taxpaying commuting citizen paying a butt ton in taxes and would love to see some new solutions to a major issue.

This issue helps address the problem proactively and it will, just wait an see- improve over time the more and more it gets used.

Jason Baker
25th June, 2012 @ 09:18 am PDT

There are better alternatives like The Python 5000 machine made in Canada

wiarus2000
25th June, 2012 @ 01:35 pm PDT

@ Jason - You're paying a butt ton in taxes because the people in charge of the money don't know how to manage it. They come up with brilliant plans such as using aspalt instead of concrete for roads because it is cheaper on the front end, yet they don't worry about what it will cost for maintenance on the back end until it's too late to properly maintain the roads.

Do you really believe that your taxes will go down simply because they have a machine like this?

Rt1583
25th June, 2012 @ 08:18 pm PDT

How many council workers will go on strike now they know this is in the pipeline???

Australian
25th June, 2012 @ 10:50 pm PDT

Prevention is better than a major repair, and with lower labor costs, machines like this could be operated at night when the traffic and the impact of lane closures is at it's minimum.

Bring in contract signs/witches caps/automated traffic signals if needed for an overnight lane closure. One hour to put them out, one hour to collect, then one man to operate the machine for the night in a 10 hour shift with 8 hours of machine operation. 3mph x 8 hours= 24mile (4.8kph x 8 hours = 38.4km), that's a fair whack of road maintenance with very little labor cost.

@Rt1853; In a lot of cases, drivers are driving over, over band repairs as soon as the crew move on. most of the time, this sort of repair is done with out any road closure, with only rolling signage on the crew/repair truck being used plus a ute or some thing to act as protection to the workers. For FWY/HWY repair, damn site cheaper than completely closing the same lanes, bring in signage + bobcats, trucks to clear rubble, asphalt ripper or converter, more trucks with asphalt, asphalt-paver, rollers (steel vibrate/multi etc etc).

And as far as health issues are concerned, you try sitting on top of an asphalt paver in the stinking heat, sucking in diesel and rubber fumes all day, while doing major repairs. Take it from me; it sucks big time and possibly part of the reason I cough flem all day every day!!!!

@ihateorange As for the repair shown in the images "over banding", does not look any worse than a repair done with any hand wand work I have seen or completed. No matter how close you put the wand spray nozzle to the crack, you will still get run over each side of the crack, in fact it creates a better seal and is preferred. It is also next to impossible to keep the straight line of a spray beam exactly in line with a crocked crack. Add to that, all wands dribble once the valve is closed.

@wiarus2000; The Python 5000 is for pot hole patching, not an over-band system which helps prevents pot holes occurring.

As they mention, there are a few bugs to tweek yet, but once done, should be a great addition to any road maintenance program. Add the likes of the Python 5000 and you cover a wide scope of road repair, with very low labor costs.

ELM
26th June, 2012 @ 04:33 am PDT

This is so cool! Finding someone to do reasonable priced and high quality sealcoating in Albuquerque is a hard thing. It seems like not many people do it. This could take care of everything though. I would definitely support implementing this to fix roads!

hjames1623
4th March, 2013 @ 03:39 pm PST
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