In the past, the construction industry had contributed to a large part of landfill waste, but the I-75 Modernization project is taking steps to reduce that waste and other environmental impacts. By rebuilding pavement and bridges in the same location as the original highway, and providing additional safety, geometric, and mobility enhancements, the I-75 Modernization project is recycling and reusing the original material.
What are some ways the project is focusing to reduce landfill waste?
Key areas to reduce landfill waste are to recycle concrete, steel, sub-base, and asphalt. The four recycling efforts include the contractors recycling 70- to 100-percent of:
- Existing Portland Cement Concrete pavement to be used as a road base for new road construction.
- Existing hot mix asphalt to be used to construct the tunnel site or other work areas.
- Existing base and sub-base road material will be used as backfill material for drainage structures and embankments.
- Steel obtained from demolition operation to be used on the project or for other steel products in southeast Michigan.
Recycled Pavement and Aggregates
When the pavement is removed, broken up, and stored on the project, the material is recycled and can be used as backfill. Concrete is made from aggregates (stones), cement, and water. Mixed and allowed to harden, typical concrete roads and bridges last for up to 50 years before time and pressure break the cement away from the aggregates, and the roads start to crumble. Water does not stay in the concrete forever and the chemical reaction with cement stops. Cement cannot typically be recycled once the chemical reaction ends, but the aggregates are still useable! Engineers and contractors have found a way to remove all the aggregates from old concrete through the use of big machines that crush up the concrete and remove the old aggregates. They can then be used to help reconstruct the roadway base or be used in new concrete mix for the roadway surface. Doing this means that aggregates do not have to be mined, transported on ships or barges, trucked to the project, and moved to where it’s needed. Imagine all the gasoline and diesel fuel that is not burned and the emissions that are not created because all those steps can be skipped! The process of reusing the aggregates from the old roadway reduces these environmental impacts as well as reduces scarring of the earth by the mining process. The I-75 Modernization project is using recycled aggregates in the layer directly under the concrete, and in the concrete itself, maximizing the use of readily available materials, and limiting environmental impacts.
On-site portable concrete plants
Typically, concrete plants are near rock quarries (mines) or areas where there is a lot of construction. On this project, the contractor is using portable concrete plants. As part of the pavement recycling process, once the recycled aggregates come from the crushers, some are diverted to concrete mixing facilities (plants) that mix aggregates, water, and new cement into concrete to be used for the roadways and bridges. Using portable concrete plants reduces the fuel consumption of concrete trucks and saves the contractor time. The longer a concrete truck trip is, the more fuel is used, so on this project, portable concrete plants reduce fuel usage and emissions that can be harmful to the environment.
|Figure 1: Portable Concrete Plant located at Rochester Road|
Recycling of reinforcement steel
The original roadway and bridges were concrete construction, with steel added to reinforce it providing additional strength and durability. Today, new steel is very costly to manufacture and creates many environmental impacts ranging from mining iron ore, deliveries to ports, shipping and transporting to steel mills, burning fossil fuels such as coal to heat and create steel. During the crushing process of recycling the old concrete, the steel is sorted out of the crushed material and recycled. The environmental impacts of creating new steel for the project are drastically reduced by recycling the millions of tons of steel from the old roads, barrier walls, guardrail, and bridges on this project. All the recycled steel is transported to steel mills in southeast Michigan that melt it down to create a variety of new steel products, from car parts to steel beams.
What are some ways the project is reducing environmental impacts?
There are several environmental measures to protect and enhance the natural environment, including:
- Detention Ponds:
- Drainage design has introduced controls and countermeasure plans to prevent pollutants from the project from entering water bodies.
- Remediation of contaminated areas within the project’s right-of-way and to prevent future contamination.
- Trees, Landscaping, and Habitat Protection:
- Trees will be planted. Landscaping will be improved along the corridor providing, habitat and support birds and other wildlife.
- Fencing will be installed to minimize vehicle-wildlife interaction.
- Habitat loss is minimized by controlling the project footprint and planting vegetation along roadsides.
- Vegetation clearing is timed to avoid the breeding season for migratory and non-migratory birds.
- A bird sweep is being conducted by a qualified biologist to identify wildlife and habitat prior to grass mowing / vegetation clearing and bridge demolition operations.
- Controlling invasive species by removing existing invasive species along the project’s right-of-way and selecting locally appropriate, non-invasive plants for landscaping along the project corridor.
- Carpool lots: They will facilitate carpooling and fewer cars on the road, which will result in reduced greenhouse gas emissions and improved air quality.
- To the extent possible, excavated earth from the project is used in other locations within the project limits. This is not only a cost savings but is also an environmentally friendly approach that reduces the amount of fuel used to truck soil off the project and reduces the amount of truck traffic on the roadway.
- Storage and Drainage Tunnel: The tunnel will capture stormwater from the I-75 freeway, separating the water from the local Oakland County collection system, therefore, reducing the number of combined sewer overflows into the Red Run Drain, Clinton River and ultimately Lake St. Clair.
This project is constructing several new detention ponds to slow down stormwater runoff. These are being constructed to collect storm water and melted snow runoff from the roadways and bridges. The intent of these ponds is to collect storm water and hold it in place long enough to allow pollutants to settle out of the water and collect at the bottom of the ponds. Doing so keep pollutants from entering larger streams, creeks, rivers, and lakes where it could cause long term damage to these types of ecosystems. The I-75 project has several of these set to be constructed. These were not included in the original construction of the roadway, so adding these today is a significant improvement to cleaning runoff and improving the water quality of storm water runoff.
Trees and Landscaping
Another environmental benefit will be the planting of trees native to Michigan. Every section of roadway that had removal prior to construction, will be evaluated for replanting, with some areas receiving more than what was removed. Trees reduce carbon dioxide which can be produced by vehicles using the nearby I-75 roadway. Having more trees will mean additional levels of carbon dioxide will be processed out of the air. The trees and landscaping will provide habitat and support birds and other wildlife.
Controlling invasive species along the project’s right-of-way and selecting locally appropriate, non-invasive plants for landscaping along the project corridor.
|Figure 2: Tree Plantings at Adams Road|
What are additional sustainable objectives that the project is providing?
The project enhances safety, mobility, economies, and livability throughout the region. It was planned and designed with specific sustainability objectives in mind:
- High-Occupancy Vehicle (HOV) lanes (north of 12 Mile Road to north of Square Lake Road interchanges) and an additional general-purpose lane (M-102 to 12 Mile Road) to reduce congestion and travel time. Visit our HOV Highlight page for more information.
- Flooding risk will be mitigated through construction of an underground drainage tunnel. View our Tunnel Highlight page for more information.
- Noise walls built to help reduce noise pollution.
- Diverging Diamond Interchanges (DDIs) will enhance safety and reduce delays. View our DDI Highlight page for more information.
- Connectivity for the community has improved pedestrian crossing structures located over and on each side of the freeway.
|Figure 3: Reconstructed Orchard Avenue Pedestrian Bridge|