StarTribune Online Magazine recently reported on the wrenching debate that is playing out among USA state officials trying to stretch limited transportation money to fix or replace as much roadway as possible.
Transportation funding has lagged as road conditions have deteriorated in Minnesota and many other USA states. An example: 40-year-old concrete on I-94 between downtown Minneapolis and Brooklyn Center, Minnesota: the joints were fixed and fresh asphalt laid over but, the pavement buckled in five places from the 90-degree (90°) June heat before traffic even started to roll over the new multimillion-dollar freeway … leading to higher costs and more delays.
Tim Clyne, MnDOT Pavement Engineer said concrete bubbled up due to the heat in early June in at least five locations on I-94. The contractor had to grind out the distressed concrete below the surface and then patch the 9-inch holes with asphalt, not concrete. “That should hold up to the traffic load,” Clyne said. “This is old concrete, and every summer it gets hot and joints lock up and pop.”
Tim Nelson, Project Manager said that the asphalt made the pavement hotter and contributed to the blowups, but that once traffic returned, it helped to keep it cooler, lessening the chances of more buckles on the newly paved lanes.
“We are undercapitalized,” said Charlie Zelle, Commissioner–Minnesota Department of Transportation (MnDOT). He said the state is in “patching mode” because of the funding shortfall. According to TRIP (The Road Information Program), a national transportation research group, 44% of Minnesota’s major metro-area roads are in poor or mediocre condition due to lack of funding, and the state is facing a $2.8 billion transportation shortfall over the next four years. In 2017, the Legislature authorized only $600 million in new funding for roads and bridges. In many cases, the debate comes down to this: an asphalt patch or a concrete overhaul.
Charlie Zelle said he’d like to redo I-94 and other heavily traveled roads with concrete, but the decision to patch joints and cover concrete with asphalt is a matter of time and resources. The construction time of the asphalt overlay on I-94 will last as long as a full concrete rehab, he said. “We are keeping traffic open, and even though it is pretty disruptive, it is going to be done in a year, with less traffic disruption, that is a pretty easy choice.”
But, Matt Zeller, PE, Executive Director-Concrete Paving Association of Minnesota (CPAM) and a former employee MnDOT, has a problem with the state’s “Band-Aid” approach to fixing its highways. “They are not addressing the root cause of the concrete deteriorating. The concrete below is starting to break down and it has very little support. When the blacktop is put over the top, there is nothing to hold the asphalt up. It is a very expensive Band-Aid fix,” he said. Instead of ripping out old concrete and laying new—Zeller acknowledges a costly proposition, but one that would last another 30 to 40 years—the state routinely has covered up its aging concrete with asphalt—cheaper but lasts only 12 to 15 years.
But, Adeel Lari, Research Fellow-University of Minnesota’s Humphrey School of Public Affairs and a former Senior Manager-MnDOTAsphalt said patching is a feasible and economical solution, even if it means going back and doing the work sooner than if new concrete were put down. “It’s like our personal budget. We have only so much money … ‘You can buy a new car, or fix the one you have and have it last another three years’ … those are the kinds of decisions MnDOT is making.”
Charlie Zelle added that by opting for the patching and reconstruction in bits and spurts, motorists will likely experience construction throughout the metro area’s I-94 corridor annually for the next 15 years.
Matt Zeller pointed to other projects where MnDOT has taken the asphalt Band-Aid approach, only to be back redoing the work sooner than planned. In the 1990s, MnDOT applied asphalt over concrete on I-394. The asphalt began to break apart a decade later, exposing chunks of concrete. MnDOT applied another thin layer of asphalt in the mid 2000s. By 2015, when I-394 was rife with potholes and divots, the agency stripped off the asphalt, dug out deteriorating joints, replaced them and shored up the concrete around them. The agency then smoothed out the surface using the diamond grinding process.
Matt Zeller said aside from building a new freeway from scratch, a better solution would have been for MnDOT to do a concrete overlay, meaning placing new concrete over the existing concrete. That would provide structural integrity for years to come, he said.
‘This is not a perfect fix’: With the I-94 issues in June, MnDOT sent the contractor back to make fixes to the road it had just repaired. As work proceeds on I-94, will the freeway continue to buckle? “It’s possible we will see more bumps in the road,” Clyne said, at least through late summer. But he added: “…This is not a perfect fix … We are trying to keep an old road in good condition.”
To read the entire article, please go to: http://www.startribune.com/a-freeway-s-concrete-dilemma-patch-vs-redo/432568973/
About TRIP: Founded in 1971, TRIP is a private nonprofit organization that researches, evaluates and distributes economic and technical data on surface transportation issues; promotes transportation policies that help relieve traffic congestion and its impact on air quality, improve road and bridge conditions, make surface travel safer, and enhance economic productivity. TRIP is sponsored by agencies involved in highway and transit engineering and construction, labor unions, and organizations concerned with an efficient and safe surface transportation network that promotes economic development and quality of life.
For the USA individual State Information & State Reports, please click on the map above or go to: http://www.tripnet.org/state-info-reports.php.