|Hammer Time. Afghanistan project is the largest of its kind in the world, experts say. (Photos courtesy of Louis Berger Group)|
Rubblization—or the process of breaking up an old portland cement concrete highway into aggregate-sized chunks, compacting it and paving over the newly created �base� with asphalt concrete—is quickly becoming a hot rehabilitation tool around the world. In just the past few months, several of the world�s largest rubblization projects are shaping up from Middle America to the Middle East.
The Illinois Tollway just completed a 31-mile improvement project along Interstate 88 last month, near the Iowa border. As part of a $5.3-billion statewide program, the four-lane highway was rubblized and repaved in five months at a cost of $48 million—roughly $22 million less than state engineers had estimated for a complete PCC rebuild. The method also mitigated rapidly changing prices for raw materials. �By doing it fast, we can take advantage of the market conditions,� says Jeffrey Dailey, the tollway�s chief engineer.
Even though Arkansas has far more rubblized pavement than most other states, at approximately 370 miles, highway experts claim that I-88 was the largest single rubblization job ever performed in the U.S. Several years ago, processing 400,000 sq yd of pavement would have been a major project, says Matt Shinners, vice president of rubblization contractor Antigo Construction Inc. of Antigo, Wis. But the Illinois highway, which his company rubblized, came to 1.4 million sq yd. �It was an extreme amount of work done in a short amount of time,� he says.
Only a handful of contractors specialize in rubblization so it is not surprising that they usually manufacture the equipment used to bust up roads into �rubble.� The machines vary in the way they do it, but the end result is essentially the same.
Antigo has 26 such machines working around the world. The company uses a multi-head breaker that can rubblize a rate of about two miles per day. The 47,000-lb units have 16 hammers that alternately raise up and slam down on the pavement like a giant meat tenderizer.
Another type is a high-frequency hammer that �vibrates� and breaks up to 26-in.-thick slabs at a rate of about one mile per day. �We�ve been doing it 20 years and it is continuing to get more popular,� says Ron Pattison, vice president of Resonant Machines Inc., Tulsa.
A U.S. innovation, the method is gaining favor elsewhere, too. According to Shinners and Pattison, Afghanistan is home to the largest highway rubblization job in the world, along a 346-miles trade route that links Kandahar to the western city of Herat. The project is split into five contracts issued to Saudi Arabia, Japan and the U.S. Using Antigo breakers, the total rubblization package adds up to about 274 miles.
People traveling along the 40-year-old concrete highway were lucky to get average road speeds of 30 mph due to years of war, poor maintenance, and unregulated truckloads, according to Eric Cook, deputy project manager for Louis Berger Group, East Orange, N.J. �Originally, it took about 18 hours to get from Herat to Kandahar,� he says.
Berger holds a $700-million contract with the U.S. Agency for International Development to manage reconstruction of Afghanistan, including its roads, says Group Vice President Larry Walker. It completed the Kabul-Kandahar Highway in 2004 and hopes to wrap up its sections of the Kandahar-Herat Highway this year. Although the road still needed major shoulder work and extra aggregate hauled in, �the condition was really perfect for rubblization,� Walker says.