Is your city requiring both asphalt and concrete pavement bids when fixing or building streets? If not, the bigger question is, why not?
Elected officials say taxpayers are looking to get the biggest bang for their buck when it comes to the cost of government. That includes the cost of building and repairing streets.
For that reason alone, cities and counties should require bids for both asphalt and concrete pavements. And those bids should include a life cycle cost analysis for road construction or repair projects. Doing so helps them determine whether using asphalt or concrete materials is the more cost-effective, sustainable investment.
Life Cycle Cost Analysis
The life cycle cost analysis considers the pavement’s initial cost, as well as the projected maintenance and reconstruction costs over the life of the road. Ultimately, it helps answer the question: Which design alternative – asphalt or concrete – results in the lowest total cost over the life of the project?
According to a 2012 American Public Works Association report, getting both asphalt and concrete bids often lead to reduced cost and an increase in a projects’ sustainability rating.
The concrete industry itself acknowledges that its product often has a higher initial cost than asphalt, but points to life cycle cost analysis to show that concrete generally has a longer useful service life and fewer maintenance costs over the life of the project. Read more here.
But the cost is just one measure of sustainability. What about the environmental impact of a road project?
Another tool being used helps cities determine the societal cost of concrete and asphalt is the environmental life cycle assessment. This rating includes the environmental impacts of using concrete or asphalt.
These two tools provide two very different assessments. The life cycle costs analysis measures the cost-benefit ratio; the environmental life cycle assessment helps measure the environmental footprint of a road project. Yet both tools help determine whether concrete or asphalt materials give taxpayers the biggest bang for their buck.
The Minnesota Department of Transportation (MnDOT) and Waseca County recently reached a turnback agreement giving custody and care of the old Trunk Highway 14 (Elm Avenue), back to the county. The negotiated transfer includes significant updates to the once highly traveled and now tired and worn roadway.
A Highway 14 bypass that circumvents the south-central Minnesota city of Waseca, population 9,074, was constructed several years ago.
This Elm Avenue concrete reconstruction project will likely span two construction seasons; it started in 2017 and will be complete in fall 2018 or spring 2019. The City of Waseca is coordinating and designing this undertaking, as the roadway falls within city limits.
City tapped into several funding sources to pay for turnback project
According to Consulting Engineer Joe Palen of Stantec Consultants in Rochester, Minn., funding came predominantly through MnDOT and their portion of the turnback.
The city funded its share of the project through a $1.27 million federal funding grant, low-interest loans from the Drinking Water and the Clean Water revolving loan funds administered through the state’s Public Facilities Authority and local utility funds. These funds were used to offset the costs sanitary sewer, water main, stormwater, lighting and sidewalk improvements that were constructed as part of the project.
The Old Trunk Highway 14 improvement project includes the replacement of the road surface with concrete, which was specified for the project from the start, and significant infrastructure and traffic safety upgrades.
The use of concrete was established in the turnback agreement made between MnDOT and Waseca County, according to Palen.
He said, “One of the main benefits is the longevity of the product along with reduced maintenance costs. There’s a decent amount of truck traffic running through the corridor. I think those were probably some of the considerations when specifying concrete for the road surface.”
Ulland Brothers Inc., Albert Lea, Minn., was the low bidder for the project at just over $18,298,000 and was awarded the contract in May of 2017. Hoffman Concrete, Mankato, Minn., was subcontracted to perform the concrete work.
Start: June 2017
Anticipated Completion: Spring of 2019
Concrete depth: 7-inch concrete pavement
Total project length: 3.4 miles
Total concrete placed: 77,150 sq. yards
Owner: Waseca County
City of Waseca, Waseca County & MnDOT
Project Lead: Mark Duchene Waseca City Engineer (former)
Minnesota cities and counties are turning to partial- and full-depth repairs to extend the lives of their concrete streets and roads.
In some cases, the roads were nearing the end of their projected service life. In others, the concrete streets have served their communities far longer than ever expected.
Officials perfected the concept of concrete repair in Minnesota in the mid-80s, said Matt Zeller, executive director of the Concrete Paving Association of Minnesota. Rehabilitation allows cities and counties to take care of their original investments.
“It allows them to add years to the life of the pavement, rather than having to replace it,” Zeller said.
Waseca County turned to partial- and full-depth repairs to fix two roads last summer. A 6.5 miles stretch of County State Aid Highway 3 (CSAH 3) between Janesville and Elysian, was 30 years old and showing its age because of truck traffic, and salt and sand use. The other, a four-mile section of CSAH 7 near Morristown, estimated to be about 20-years-old, had developed some joint issues.
City expects pavement to last another 20 years
Some 75 miles north, the City of Minneapolis completed two concrete street rehabilitation projects – one in the Waite Park neighborhood and at Oliver and Penn Avenues South. In both cases, city officials expect the work to extend the life of the concrete by 20 years or more.
On both projects, crews finished the work by diamond grinding the road surface to improve skid resistance, reduce noise and increase safety.
Zeller said diamond grinding was developed for highways. Using it in cities is a relatively new practice, he added, saying that diamond grinding gets the pavement back to a nice, smooth surface.
There are concrete streets in Owatonna that were rehabbed 30 years ago — long before it was a mainstream idea. Zeller said the public works director knew city streets didn’t require the same degree of rehabilitation as highways.
“The traffic isn’t as heavy and the vehicles don’t drive as fast as they do on the highway. So he’d cut out a small section and place new concrete.”
Many of practices developed in Owatonna are now part of the Minnesota Local Road Research Board’s concrete standards, Zeller said.
One way to cut road maintenance costs is to convert deteriorating paved roads back to gravel roads. It seems unthinkable, but is it?
As roads paved decades ago deteriorate and road maintenance budgets stagnate, unpaving looks like an increasingly economical — if initially unpopular — option, according to a recent MinnPost article by Greta Kaul.
The practice of converting paved roads to unpaved is relatively widespread nationwide. Citing a 2016 report by National Academies of Science, Engineering and Medicine’s Transportation Research Board, Kaul reported that at least seven Minnesota counties have converted paved roads back to gravel roads. And more are considering the prospect.
Counties, townships maintain majority of roads
Overall, elected officials in Minnesota are responsible for more than 135,000 miles of city, county, townships and state roads. While much attention is focused on state roads, they account for less than 10 percent of all roads in the state. Counties maintain about 45,000 miles of road and townships maintain another 60,000 miles.
Nationwide, the report found nearly 70 projects in 27 states that unpaved 550 miles of road. And that has researchers developing a guide to help local officials decide when it’s safe and cost-effective to unpave roads.
For now, economics are driving the decisions. When Freeborn County officials decided to unpave what was once a two-mile stretch of asphalt on County State Aid Road 49, there wasn’t money in the budget to fix the pavement.
No engineer wants to unpave a road, Freeborn County Engineer Sue Miller told MinnPost. It’s more than a reduction in the level of service to everyone who uses the road.
With the cost of adding gravel and grading, Miller said, it’s often more expensive in the long-term. The difference is when the money is spent. Gravel doesn’t require the same kind of up-front investment that building or doing a big maintenance project on asphalt does.
Reducing street maintenance costs and eliminating potholes rank high on the City of Pipestone’s public policy agenda. So when the city needs to rebuild a street and the infrastructure below, it’s been turning to concrete.
You might say: The city is building for the future.
“We are looking at the extended life of a concrete street,” said City Administrator Jeff Jones. And in some cases, that means replacing an asphalt street with a concrete one.
That was the case with its 2017 street project in the Hill Elementary School neighborhood. In addition to new streets, the city needed to replace its deficient and/or undersized underground water, sanitary sewer and storm sewer utilities on Seventh Avenue SW, Ninth Street SW, and 11th Street SW.
City requires asphalt and concrete bids
When the city put the project out for bid, it required both asphalt and concrete bids for the pavement.
“The city wanted to see what the cost difference was, knowing the life of concrete is longer,” said City Engineer Travis Winter of Bolton & Menk. And while asphalt prices have been dropping elsewhere, Winter said, he’s seen asphalt-paving projects in the region come in at higher costs the last few years.
Pipestone, a community of about 4,300 residents, is located in southwestern Minnesota. Many cities in the region are home to ready mix plants.
Availability factors into pricing, said Dan Scotting, Buffalo Ridge Concrete Plant Manager and part owner of the company.
“Unless there is a larger, asphalt project set up by MnDOT in the region, asphalt has to be trucked up to 40 miles,”said Scotting.
“All anybody wants is an opportunity to bid and make sure cities are comparing apples to apples,” Scotting said. Factoring in the cost of maintenance over the life of the street provides an apples-to-apples comparison.
“And frankly, cities are getting better bids when they require both because there is more competition.”
Winter said that while concrete generally costs about 3/4 more on the front end, it requires little or no maintenance. So at the end of 50 years – the life expectancy of a concrete street — the cost of asphalt and concrete are about even.
MnDOT reports that the average life expectancy of their concrete pavements is 27.5 years before repair while asphalt pavements have an average life expectancy of only 15.5 years before repair.
Concrete is saving Pipestone money
Winter’s projections were about on target: For this project, paving with concrete cost about $350,000 or about 60 percent more than the asphalt bid. That’s about $30,000 more per block paved. But when the city considered the costs of maintaining the asphalt street for 50 years, the city is projecting an overall cost savings of $10,000 per block.
As Winter explained, if the city had selected the lower cost asphalt, two major maintenance projects — mill and overlays to the asphalt — would be required, adding another $40,000 per block to the initial cost.
“If I get any pushback from residents, it’s that we are building more of a street than we need,” Jones said. But once we explain the difference in what’s required to maintain an asphalt street vs. a concrete street, in both terms of work and cost, they seem to understand.
It’s a matter of education, said Jones, adding, “Once they understand, they are generally supportive.”
The project cost totaled $3.07 million, including engineering fees. Roughly 20 percent of the cost will be assessed to property owners. The city purchased bonds to finance the remaining cost.
June 2017 –November 2017
Concrete depth: 6 inches with 6 inches of Class 5 Aggregate sub base and 6 inches of select granular borrow
Total project length: .85 miles
Total Concrete Placed: 3,632.5 cubic yards (CY), including concrete used for pavement, curb, gutter; another 684 CY for driveways and sidewalks
Owner: City of Pipestone Project Lead: Travis Winter, Pipestone City Engineer of Bolton & Menk, Fairmont Project Designers: Bolton & Menk, Fairmont, MN Prime Contractor: Quam Construction Company, Willmar, MN Concrete contractors: Hulstein Excavating, Edgerton, MN and Hisken Construction, Marshall, MN Ready Mix Concrete Producer: Buffalo Ridge Concrete, Pipestone MN