Utah DOT Using Recycled Concrete for Highway Project

The Utah Department of Transportation is recycling old concrete on the site of its Bangerter Highway project to help build the highway’s new interchanges. 

[Above photo by Utah DOT]

“In the past all of this concrete would have gone to waste and now is being recycled and reused for other projects,” noted Robert Stewart, director of Utah DOT’s Region 2, in a statement. “This pavement has been here for 30 years and it’s a great to be able to give it new life.”

He noted that construction crews have been working every day for the past five months on the recycling process, with Utah DOT opting to recycle the material on site instead of hauling off the material to another location to reduce the number of truck trips in the area.

To recycle concrete for reuse, the project’s construction crews use heavy machinery to break up the old sections of the highway, placing that material into an onsite crushing machine equipped with a large magnet inside to separate the concrete from the metal rebar, which is also recycled.

Once all the large cement chunks are crushed into tiny pieces, Utah DOT reprocesses the material into a road base for the new interchange. 

“We are taking the old Bangerter Highway, crushing it up and making it into a product to put into the new Bangerter Highway,” said Jake Nielson, contractor project manager on the Bangerter 4700 South project. “What most people don’t know is that most of the materials in our highways are 100 percent recyclable, whether that’s concrete or asphalt.”

Utah DOT noted that, for more than a decade, it has been working to eliminate stoplights on Bangerter Highway by converting intersections into interchanges.

As Bangerter Highway is one of the Salt Lake Valley’s largest north-to-south corridors – moving an average of 60,000 vehicles per day – removing stoplights and converting all intersections into freeway-style interchanges will enhance safety and help keep traffic moving in the ever-growing west side of the Salt Lake Valley.   

State departments of transportation across the country are involved in a variety of material recycling and reuse efforts.

For example, the Idaho Transportation Department is engaged in a broad effort to develop environmentally-friendly solutions that reduce plastic waste from entering the natural environment; particularly where infrastructure projects are concerned.

For instance, the agency is now using biodegradable erosion control loose weave “blankets” without joints that allow snakes and other wildlife to easily move over or through them. Those “blankets” play a key role in the agency’s Erosion and Sediment Control or ESC practices that prevent soil loss and reduce sediment-laden stormwater runoff in and around transportation infrastructure.

In 2023, the New Jersey Department of Transportation released a video detailing how its use of “foamed glass aggregate” provides a multitude of green benefits to the state – especially as the material is made from recycled glass bottles.

The Illinois Department of Transportation began working with the Illinois Center for Transportation in December 2021 to develop more “sustainable pavement practices,” which includes ways to incorporate more recycled materials such as plastic into asphalt mixes.

Their joint project – dubbed “R27-196-HS: Rheology-Chemical Based Procedure to Evaluate Additives/Modifiers Used in Asphalt Binders for Performance Enhancements: Phase 2” – investigated methods to “soften” asphalt binder to reduce pavement cracking.

As recycled materials are added to hot mix asphalt, the asphalt tends to harden and become brittle, potentially leading to premature cracking. As a result, the project’s researchers began testing the use of different “modifiers” or softening additives to asphalt binders to improve long-term pavement performance, especially when recycled materials are used in the mix.

Meanwhile, the Pennsylvania Department of Transportation wrapped up a pilot project in 2021 that used pellets made from grocery bags, milk jugs, and other recyclable plastics in an asphalt reconstruction project.

Those pellets were added to the asphalt in two quarter-mile test sections of the project at the entrance to Ridley Creek State Park, about 15 miles west of Philadelphia.

Winners Named in KYTC Adopt-A-Highway Art Contest

The Kentucky Transportation Cabinet recently saluted the 12 student winners of its 2023 Adopt-A-Highway Art Contest; winners were chosen from a pool of 900 entries statewide from students aged five to 18.

[Above image by KYTC]

The agency said this annual contest not only allows students to showcase their artistic talents but helps promote the important message of keeping roadsides free of litter.

“We’re thankful to have young and talented Kentuckians lend a hand at sharing an important message to encourage us all to do our part to keep Kentucky beautiful,” said Governor Andy Beshear (D) in a statement.

“Litter-free roadsides do more than protect our scenic byways; they also keep harmful materials from washing off roads and sidewalks and into our drinking water,” added KYTC Secretary Jim Gray. “We’re grateful to have students be part of the solution of maintaining a clean and safe environment.”

KYTC said the top finishers in each of the four age divisions for the 2023 contest – which centered on the theme “Can it, Kentucky” – will receive a $100 gift card, while second- and third place finishers will each receive a $50 gift card. First through third-place recipients for all age groups will have their pieces displayed at the KYTC Office Building in Frankfort, KY.

State departments of transportation across the country use a variety of student-focused contests and programs to engage elementary- through high-school students in roadway litter reduction efforts.

For example, the Missouri Department of Transportation is now accepting entries from students in kindergarten through 12th grade to participate in the agency’s 2024 “Yes You CAN Make Missouri Litter-Free” trash-can-decorating contest.

The contest – part of MoDOT’s annual “No MOre Trash!” statewide litter campaign, held annually in April – encourages school-aged kids to join in the fight against litter by decorating a large trash can with the “No MOre Trash!” logo and a litter prevention message using a variety of creative materials. Schools, or home school programs, may submit one trash can entry in each competition category: grades K-2, 3-5, 6-8 – and new this year is grades 9-12.

First-place winners from each competition category receive $200 awarded to the sponsoring schools. All first-place winners are then eligible for a grand prize of $600 and a trophy awarded to the sponsoring school. There is no entry fee for the contest, MoDOT noted in a statement, and participating school groups must submit a completed entry form online with up to three photos and a release form by March 15.

State DOTs also engage in other initiatives to remove trash and debris from the roadways under their jurisdiction.

For example, the Mississippi Department of Transportation recently launched a new anti-litter webpage as part of a renewed statewide anti-littering campaign that kicked off in August – a “one-stop hub” that contains information about the state’s Adopt-a-Highway program, Mississippi litter statistics and resources, stormwater pollution information, anti-litter resources for school teachers, and much more.

Then there is the Tennessee Department of Transportation, which recently celebrated the 40th anniversary of its “Litter Grant Program.” That program – started in 1983 – provides funding to all 95 counties within the state to pay for a wide variety of litter-related efforts, such enforcement; cleanup and recycling events; and litter prevention education campaigns.

Meanwhile, in April, the Illinois Department of Transportation launched a new public outreach effort called “Think Before You Throw!” as part of its ongoing awareness campaign to reduce littering on state highways and roads.

The “Think Before You Throw!” initiative aims to reduce roadside litter along the state’s more than 150,000 miles of roads by raising awareness of the negative environment impact of trash, for both state residents and the nearly 100 million tourists who visit annually, the agency said.

And, in March, the Maryland Department of Transportation launched “Operation Clean Sweep Maryland,” a new initiative that seeks to nearly double the frequency of litter pickup and mowing efforts along state roads.

This new effort – which began in the Baltimore and Washington, D.C., regions – is under the purview of the Maryland State Highway Administration, one of Maryland DOT’s modal divisions.

AASHTO Re:source Podcast: Hawaii DOT & ‘Plastic Roads’

The AASHTO re:source podcast recently interviewed Ed Sniffen (above), director for the Hawaii Department of Transportation, for a two-part episode about how his agency is testing the incorporation of recycled plastics into its road paving processes. To listen to part one of this two-part podcast episode, click here.

[Above image by AASHTO]

AASHTO re:source – which launched this podcast series in September 2020 – is a major technical service program of the American Association of State Highway and Transportation Officials. It provides services and tools through three major programs: the Laboratory Assessment Program, the Proficiency Sample Program, and the AASHTO Accreditation Program.

Sniffen – who previously appeared on the AASHTO re:source podcast in February to discuss his agency’s resiliency planning efforts – said using recycling plastics as part of Hawaii DOT’s mix of paving materials is “part our never-ending quest to be greener” in its road construction and maintenance operations.

“When we started looking back at the pavements on our system, [we saw] that every seven to 10 years, we have to rip out that upper layer and process another layer in. So we tried to see how we can do better,” he explained.

“We started using better materials and making sure that we reconstructed roadways rather than just putting in a ‘mill and fill.’ And that’s helped us tremendously in ensuring that we don’t have to do as much work as CO2 [carbon dioxide] intensive as often,” Sniffen noted. “Now we’re starting to use a stone matrix, asphalt, and polymer mix to create ‘modified asphalts.’ It’s going to give us that 20 to 25-year lifespan we’re looking for.”

Appointed to lead Hawaii DOT in December 2022, Sniffen is a recognized state DOT leader on the topic of resilience and “green” construction initiatives.

He serves as the chair of the Committee on Transportation System Security and Resilience for the American Association of State Highway and Transportation Officials and has testified on Capitol Hill about a variety of infrastructure resiliency issues as well.

Sniffen also participated in a knowledge session on infrastructure resilience hosted during AASHTO’s 2022 Spring Meeting in New Orleans.

How Arizona DOT Reuses Materials

The Arizona Department of Transportation recently outlined how it reuses a variety of highway construction materials – such as asphalt, concrete, and steel – to reduce overall transportation project costs and preserve the environment.

[Above photo by the Arizona DOT]

“We reuse as much as we can so nothing goes to waste,” explained Kole Dea, senior resident engineer with the Arizona DOT, in a blog post. “If something can’t go back into the project, then it’s recycled.”

Dea used the I-10 Broadway Curve Improvement Project to highlight how the agency reuses and recycles highway construction materials – both as part of the same project as well as externally on different projects.

For example, when construction began on the I-10 Broadway Curve project in summer 2021, crews removed the rubberized asphalt from the surfaces of I-10 and US 60 in the project area. That work created 1.3 million square yards of asphalt millings, which then formed the base layer for temporary haul roads in the project area. Millings provide a strong base for trucks and equipment to drive on, and they reduce dust – another plus for the environment. Furthermore, the agency mixed those millings with dirt to build embankments to provide additional support to those temporary roadways. Outside of the project area, Arizona DOT said it uses millings on maintenance roads in unpaved areas. 

As the agency removes walls and other concrete structures to make way for new construction, they are broken up to serve a new purpose. Arizona DOT said its crews use equipment to break each piece into sizes no larger than 24 inches. Those pieces then become fill material for building up approaches for new bridges. They also fill in holes or otherwise supplement unstable materials in the project area.

The agency also removes steel rebar and other metal materials and takes them to a recycling facility – pointing out that recycled steel is as strong and durable as new steel made from iron ore.

Arizona DOT stressed that it works in compliance with state and federal regulations to ensure all reused materials do not threaten the environment. For example, the agency tests the paint stripes on milled asphalt to ensure it does not contain lead, and that old pipes or bridge structures are free from asbestos.

Several state departments of transportation have reused materials left over from highway and other transportation infrastructure projects for a variety of purposes – especially environmentally focused ones.

For example, in 2021, the Maryland Department of Transportation began oversight of contracts with two Maryland companies to make bricks, pavers, concrete highway barriers, and shoreline supports – among other structures – from dredged material cleared from a shipping channel within the Port of Baltimore.

In addition, in early 2022, the North Carolina Department of Transportation provided more than 1,000 tons of damaged concrete pipe to help the North Carolina Division of Marine Fisheries shore up two artificial reefs.

Hawaii DOT wants plastic waste to hit the road

The Hawaii Department of Transportation is moving forward on two fronts to transform plastic water bottles from beach-littering ‘ōpala’ or rubbish to recycled road material.

[Above photo by the Hawaii DOT]

Engineers are testing an asphalt mix with recycled plastic polymer on a 1.2-mile road segment in Honolulu to see how well it holds up in Hawaii’s tropical environment.

Meanwhile, Hawaii DOT is using an FHWA Climate Challenge Initiative grant to help finance its own $6 million plastic recycling research facility to turn plastic waste into road polymer and other useful transportation products.

The pilot project is the southern end of Fort Weaver Road; a two-lane bi-directional road with that carries 6,200 vehicles per day on average. The roadway was “perfect for the pilot” because the base structure was in good condition, but the wearing recourse required “significant rehabilitation or replacement,” said Ed Sniffen, Hawaii DOT’s deputy director of highways.

He explained that the agency plans to divide the roadway segment into three sections: the control section, which will be composed exclusively of Polymer Modified Asphalt or PMA; a second section incorporating plastic into the PMA; and a third section adding plastic to traditional ‘Hot Mix’ asphalt.

Once construction is finished in July 2023, researchers at the University of Hawaii at Mānoa and Hawaii Pacific University will evaluate the three sections for performance and the potential of the material to release microplastics into the environment.

“Even though we’re using a material that has been used on roads in the United States for over five years, we need to make sure the mix is right for Hawaii and our environment,” Sniffen said.

Anticipating that the pilot project will be a success, Hawaii DOT already is planning the state’s first plastic recycling facility, expected to be operational within two years.

The facility will use plastic waste found in the Pacific Ocean to manufacture pellets for roadway use, Sniffen noted, “then could potentially move into creating plastic products for other infrastructure like plastic reinforcing materials for concrete.”

That is important for Hawaii because it must import plastic pellets from the mainland while it has an overabundance of hometown plastic that serves no useful purpose.

“Keeping our own waste plastic out of landfills in a manner that will improve our roads and environment will be a tremendous benefit to everyone in Hawaii,” Sniffen added.

Several other state departments of transportation are engaged in similar plastic recycling efforts.

In November 2021, the Pennsylvania Department of Transportation wrapped up a pilot project that used plastic pellets made from grocery bags, milk jugs, and other recyclable plastics in an asphalt reconstruction project.

The pellets were added to the asphalt that covered two quarter-mile test sections of the project at the entrance to Ridley Creek State Park, about 15 miles west of Philadelphia.

In December 2021, the Illinois Department of Transportation started working with the Illinois Center for Transportation to develop more “sustainable pavement practices,” which include ways to incorporate more recycled materials such as plastic into asphalt mixes.

Both are working on a joint project – dubbed “R27-196-HS: Rheology-Chemical Based Procedure to Evaluate Additives/Modifiers Used in Asphalt Binders for Performance Enhancements: Phase 2” – to investigate methods to “soften” asphalt binder to reduce pavement cracking.

Tennessee’s ‘Tire to Trails’ Program Wins Award

The Tennessee State Parks received the Project Excellence Award from the Society of Outdoor Recreation Professionals for its “Tires to Trails” conducted in collaboration with the Tennessee Department of Transportation, which uses recycled tires in the construction of recreation paths.

[Above photo by the Tennessee DOT]

The Society of Outdoor Recreation Professionals presents this award annually to exemplary outdoor recreation projects and collaborating agencies and organizations that were key to the success. Selection criteria include unique or special circumstances; problem-solving function; level of innovation and creativity; impact or effect of a project; and collaborative team effort.

“This is a wonderful recognition of an outstanding program,” said David Salyers, commissioner of the Tennessee Department of Environment and Conservation, in a statement.

“We have seen great success with ‘Tires to Trails’ and the award is a tribute to all who have worked to make it successful,” he said.

Tennessee State Parks officials, along with those from the Tennessee DOT, cut the ribbon in June on a new hard-surface 2.5-mile-long pathway made from rubber crumbs derived from old tires at T.O. Fuller State Park in Memphis.

Volunteers and local contractors collected some 24,000 illegally dumped tires in the area around the park, transformed into “crumbs” by Patriot Tire Recycling in Bristol. That “crumb” material then went into the construction of the park trail.

This is but one of several environmentally focused projects involving the Tennessee DOT. The agency recently expanded its “traditional role” in the Mississippi River Delta Region from building and maintaining roads to include fighting litter, supporting tourism, and promoting economic development. In addition, in conjunction with the Keep the Tennessee River Beautiful and other partners, the agency established a network of 17 “Seabin” automated litter and debris removal devices across the Tennessee River watershed in March.

Louisiana DOTD Wins Award for Brine Management

Scott Boyle (seen above), assistant administrator of operations for District 2 of the Louisiana Department of Transportation and Development, recently received an award on behalf of his district’s handling of brine disposal.

[Above photo by the Louisiana DOTD. Jefferson Parish President Cynthia Lee Sheng (at left) presents a ‘Certificate of Merit’ to Louisiana DOTD’s Scott Boyle.]

Louisiana DOTD’s District 2 received the 2022 Environmental Leadership Award from the Jefferson Parish Department of Environmental Affairs for its efforts to dispose of excess brine used in winter road clearing operations to minimize the impact on the local water table.

In January, in preparation for an anticipated ice storm in the greater New Orleans area, Louisiana DOTD produced nearly 1,800 gallons of brine to combat ice on the region’s most critical roads and bridges. However, once the weather event was over, a surplus of brine remained.

“In the past, we have tried to store the brine in stationary tanks, but algae growth and the degradation of the solution from heat and sunlight prevented us from re-using the brine for future winter events,” said Boyle in a statement. “Knowing that this material needed to be disposed of responsibly, we contacted the Jefferson Parish Storm Water Management team for guidance.”

Louisiana DOTD then worked with the Jefferson Parish Bridge City Wastewater Treatment Plant – located next to District 2’s headquarters – to dispose of the brine. The mixture was disposed of on a drying bed located on the treatment plant property, filtering out a portion of the salt before introducing the salted water into the plant slowly so it would not shock or upset the wastewater treatment process.

According to Jefferson Parish, these awards recognize those individuals, businesses, or organizations that strive for environmental leadership through programs and actions that improve stormwater quality and/or quantity, thereby reducing the amount of pollution that enters Jefferson Parish waterways.
“It is an honor and a privilege to be recognized for our partnership with Jefferson Parish as [Louisiana] DOTD ensures that we are doing our part to improve our surrounding waterway quality,” Boyle said. “Actions can have significant impacts on the region that we love to live and play in.”

Tennessee DOT Helping Deploy ‘Seabins’ for River Cleanup

The Tennessee Department of Transportation has teamed up with Keep the Tennessee River Beautiful (KTRB) and other partners to establish a network of 17 “Seabin” automated litter and debris removal devices across the Tennessee River watershed.

[Above photo by the Seabin Project]

Seabin devices work continuously to skim and collect marine debris from the surface of the water. Each receptacle can remove up to 3,000 pounds of marine debris annually, while also filtering out gasoline, oils, and “micro-plastics” from the water.

Grants from the Tennessee DOT and the national Keep America Beautiful organization provided the funds supporting this deployment of the Seabin devices.

The Tennessee DOT’s contribution includes the purchase and installation of 10 devices at locations throughout Tennessee, as well as funding for two years of water-based cleanups of the river and its tributaries within the state – funding made in conjunction with the agency’s “Nobody Trashes Tennessee” litter prevention campaign.

“[Our] partnership with Keep the Tennessee River Beautiful demonstrates the link between roadside litter and debris that ends up in our waterways,” explained Joseph Galbato, Tennessee DOT interim commissioner, in a statement. “Investing in this substantial network of litter removal devices is another example of how TDOT promotes innovative solutions to making our state cleaner and keeping our waterways clear.”

In addition to the 17 Seabins deployed in Tennessee, another two will deploy on the Tennessee River in Alabama, with one other placed on one of the river’s tributaries in North Carolina.

“Until now, all of our work has only been able to prevent micro-plastics in our waterways, so we are thrilled to the Tennessee DOT and Keep America Beautiful for these – as I see it – revolutionary grants and to our partners who will be maintaining the Seabins to make this trailblazing project possible,” added Kathleen Gibi, KTRB’s executive director.

The Tennessee DOT is an agency known for funding different and innovative ways to reduce littering.

For example, in April 2021, the agency helped fund a pair of new exhibits at the Tennessee Aquarium illustrate how micro-plastics and other roadside trash can negatively affect the health of the ocean as well as rivers, lakes, and streams.

The new exhibits – housed in the Aquarium’s “River Journey” and supporting the Tennessee DOT’s “Nobody Trashes Tennessee” litter reduction campaign – include actual debris taken from the banks of the Tennessee River: the focus of its current Seabin deployment project.

NCDOT Providing Material for Artificial Reefs

The North Carolina Department of Transportation is providing more than 1,000 tons of damaged concrete pipe to help the North Carolina Division of Marine Fisheries shore up two artificial reefs.

[Above photo by NCDOT]

NCDOT sent those discarded culverts – which accumulated over the past several years as the result of an aggressive pipe replacement program in part due to damage caused by recent hurricanes – to the Port of Wilmington for eventual deployment off of the Brunswick County coast.

N.C. Division of Marine Fisheries – part of the North Carolina Department of Environmental Quality – maintains several artificial reefs that create habitat for fish and ideal fishing sites.

It said artificial reefs create habitat for fish by creating three-dimensional structures that replicate the ecological functions of food and refuge fish and other marine life need to survive and create “crucial” spawning and foraging habitat for many commercially and recreationally important fish species.   

The fisheries division has been working with NCDOT to find “new and cost-effective uses” for scrapped concrete pipe. Using that piping to build artificial reefs for marine life along the state’s coastline in a money saver, the agency noted – eliminating $65,000 in tipping fees to dispose of it in a construction and demolition landfill.

Ken Clark, an NCDOT district engineer, said the idea for donating the pipe arose during a conference for coastal resiliency. That is when he discovered the state’s marine fisheries division could repurpose his stockpile of precast concrete, barreled-shaped pipe to augment existing artificial reefs. 

“We had considered many options on how to properly dispose of this unusable material when we formed this unique collaboration with the Division of Marine Fisheries last year,” he explained in a statement. “This program mutually benefits both state agencies.”

Other state departments of transportation are involved in similar artificial reef construction projects.

For example, in 2020, the New York State Department of Transportation began helping expand a series of artificial reefs off the shores of Long Island as part of a three-year-long multiagency effort – dumping a retired tugboat, 16 rail cars, and a streel turbine on Hempstead Reef.

“[We are] proud to work with our sister agencies on this important program, repurposing transportation materials to expand artificial reefs and support biodiversity, fishing, and tourism,” explained Marie Therese Dominguez, NYSDOT’s commissioner, in a statement at the time.

“It is another example of how [our state] is taking bold steps to protect our ecosystems and foster sustainable economic growth that will benefit current and future generations of New Yorkers,” she said.

PennDOT Turning Plastic Waste into Roadway Surface Material

For several weeks now, the Pennsylvania Department of Transportation has been dumping plastic waste onto the roadway near a state park – and that is actually a good thing.

[Above photo by PennDOT]

PennDOT is wrapping up a pilot project that uses pellets (seen in above photo) made from grocery bags, milk jugs, and other recyclable plastics in an asphalt reconstruction project. The pellets are being added to the asphalt in two quarter-mile test sections of the project at the entrance to Ridley Creek State Park, about 15 miles west of Philadelphia.

The expected benefits from this project – due to wrap up by the end of November – include diverting waste plastics from landfills, helping to establish a market for recycled plastics, and extending the useful life of asphalt pavements.

“We are very pleased when we can pursue innovations bringing benefits to the public, our transportation assets, and our environment,” Mike Keiser, PennDOT’s acting deputy secretary for highway administration, explained in a recent news release.

Mike Keiser, PennDOT

The pellets are comprised of high-density and low-density polyethylene – known colloquially as Number 2 and 4 plastics, respectively – plus an additive. Common Number 2 plastic products include milk jugs, shampoo bottles, and some plastic toys. Number 4 plastics, by contrast, are lighter and best known for making grocery bags, shrink-wrap, and bread bags to package.

[Click here to learn more about how to recycle different types of plastic.]

First, those pellets are mixed together with recycled asphalt pavement or RAP, which is then heated and applied to the road surface. The entire process is “relatively consistent with conventional pavement preparation processes,” noted PennDOT Press Secretary Alexis Campbell.

The amount of pellet material can vary from job to job, usually comprising two to four percent of the asphalt binder, Campbell said. If a project uses the maximum amount of pellet material in an application, that can translate to up to three million plastic grocery bags per mile paved.

As PennDOT evaluates the project for performance and environmental properties, it is also looking for other suitable roadway locations for testing “plastic asphalt,” Campbell said.

The agency added that this pilot project is coordinated through PennDOT’s Strategic Recycling Program, funded through the state’s Department of Environmental Protection.