What is America’s Most Recycled Product?

Asphalt pavements are one of our greatest renewable resources! The U.S. recycles about 2 million tons of plastic each year while recycling and reusing over 60 million tons of asphalt.

In addition, plastic recycling alters the chemical structure, so many plastics become different types of products once recycled. Roads, on the other hand, are reusable and renewable infinitely. (1)

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Calumet County, Wisconsin Helping to Create Longer Lasting, Safer Roads

Many states are looking for methods to improve longitudinal joint performance of their pavements, since these joints often fail before the rest of the surface. With the inherently lower density at the longitudinal joints we often see pavements fail by cracking, raveling, and potholing. Lower density is synonymous with higher air voids which leads to premature failure of pavements due to the intrusion of air and water. Studies have shown that longitudinal joints in pavements are often the weakest areas of a road. (1)

A picture of a pavement’s longitudinal joint with significant damage.

Several state DOTs (Department of Transportation) are now using a materials approach to seal the longitudinal joint region by filling these air voids with asphalt content from the bottom up.

The materials approach is referred to as VRAM(2), a Void Reducing Asphalt Membrane.  VRAM is a highly polymer-modified asphalt cement that is placed at the location of a longitudinal joint before paving. As mix is paved over it, the VRAM melts and migrates up into voids in the low-density mix, making the mix impermeable to moisture while sealing the longitudinal joint itself.

Think of this materials approach and application as putting VRAM down first (asphalt content), to fill air voids in the HMA mat, AFTER the HMA has been placed. This is the innovative nature and chemistry of VRAM and why it has been helping roads last longer in more than 20 states in the United States. 

This particular project covers 10,560 feet in Calumet County, Wisconsin from US 151 to Honeymoon Hills Road.

Illinois Department of Transportation (IDOT) test pavements were evaluated after 12 years and found to have longitudinal joints that exhibited significantly better performance than the control joint sections and were in similar or better condition than the rest of the pavement. Laboratory testing of cores showed decreased permeability and increased crack resistance of mix near joints with VRAM as compared with similar mix without VRAM. The life extension of the joint area is approximately 3–5 years, and the benefit is calculated to be three to five times the initial cost.

You will note the test section (above the white line) does not have VRAM, while the section below did use VRAM. This is 15 years AFTER the VRAM was placed under the HMA at time of construction.

This project’s VRAM application began at 8:05pm with ProTack operating the 05-distributor shooting from the driver’s side. They started at address N3362 in the eastbound lane. Ambient temperature was 61F and existing pavement was 80F. ProTack applied a straight and consistent line throughout the project. VRAM width was measured with an average of 18 inches. (3)

An 18 inch application of VRAM.

The paving crew started at 11:40.  Paving equipment consisted of a Volvo P7170B paver, Sakai SW850-II – 12-ton breakdown roller and a Volvo DD25B-5-ton finish roller. Width was 12 feet.  Mix temp was 275F under the screed.

HMA is placed over the VRAM. The heat and pressure of the HMA cause the VRAM material to migrate upwards 50-75% into the HMA, filling voids with asphalt content.

J-Band® is a VRAM product from Asphalt Materials, Inc. and was created in the labs of the Heritage Research Group.

J-Band has been helping roads last longer since 2002. VRAM has been used in 20 states and the District of Columbia. 

Notes:

  1. Materials Approach to Improving Asphalt Pavement Longitudinal Joint Performance. National Academy of Sciences: Transportation Research Board 2021 Article: https://doi.org/10.1177/03611981211044451 
  2. Editor’s Notes: VRAM, Void Reducing Asphalt Membrane is referred to in Illinois as LJS, Longitudinal Joint Sealant.
  3. Depending on the situation VRAM can be sprayed at different width’s. This article notes 18” which is a typical application width for centerline applications.

Keywords: Infrastructure, Void Reducing Asphalt Material, Longitudinal Joints, J-Band, binder specifications, pavements, design and rehabilitation of asphalt pavements, asphalt, construction, asphalt pavement construction and rehabilitation, materials, binders, Asphalt Materials, The Heritage Group, Milestone, HC&M, Heritage Research Labs.

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What is a Sustainable Rehabilitation Technique for Asphalt Materials?

Bartholomew County, Indiana

Full Depth Reclamation (FDR) is a cost effective and sustainable rehabilitation technique that combines the entire bituminous pavement thickness and a predetermined portion of the underlying aggregate material into a flexible, homogenous stabilized base layer utilizing an asphalt emulsion to provide mixture cohesion and water resistance. FDR is a solution for rehabilitating roads that have poor structure. The FDR is typically followed with an overlay of hot mix asphalt.

This full depth reclamation project took many parties from start to finish. Milestone Contractors, Inc. submitted the bid, Asphalt Materials, Inc. supplied the engineered emulsion and Heritage Research Group provided the sampling, mix design and quality control. 

This particular project was on Hartman Drive in Bartholomew County, Indiana. It consisted of an eight-inch (8″) full depth reclamation on one thousand, one hundred feet (1,100′) of existing recycled asphalt pavement (RAP) road and one hundred – 70 feet (70′) of existing asphalt road. A 3″ hot mix overlay laid in 2 lifts of 1 ½” each was then placed on the new recycled roadway base. 

The County collected and placed the RAP at a depth of 8-9” from another project in the area to build the new roadway base. Milestone then pre-pulverized and graded the entire roadway at a depth of 8”. A second pass was made with the reclaimer and the engineered emulsion was injected and the emulsified material was graded and compacted. After the final cure the recycled base was overlaid with two 1 ½” lifts of HMA (Hot Mix Asphalt), striped and opened to traffic. 

Asphalt Materials Inc., is a proud member of The Heritage Group and brings nearly 65 years of experience to the asphalt industry and road construction projects. Our teams of professionals are dedicated to creating longer-lasting, safer roads with quality, reliable asphalt materials.

Our family of companies want to ensure we are leaving the world in a better place for future generations. As The Heritage Group continues to expand capabilities and investments in the sustainability space, the AMI team is also focused on sustainability in a number of different areas. We will be reporting on these in future articles.

#FDR #Infrastructure #STEM STEMEducation #Sustainability #LongerLastingRoads #HotMixAsphalt

[Note: Bids for this project opened on March 29, 2021]

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DuPage County Illinois Finds Success Protecting Pavements

Studies have shown that longitudinal joints in pavements are often the weakest areas of a road. Typically the joints are low in density, high in voids and thus are highly permeable. These areas become conduits to air and water infiltration which leads to damage and premature pavement failure. (1)

During the 2016 construction season a new method of longitudinal joint construction was specified in Illinois. This new method is a materials approach and is referred to as VRAM(2), a Void Reducing Asphalt Membrane. Applying VRAM at the time of construction helps fill the pavement voids, thus reducing the permeability in this most critical area.

As part of their evaluation, DuPage County ensured that test cores were taken on different joint constructions, such as VRAM and joint heater. DCT, I-FIT, density, and asphalt binder grading tests were performed to compare the different joint construction methods. The report summarized that the addition of the VRAM contributes to a more durable joint by partially filling the joint and adjacent mat air voids. The joint will be much less permeable and less likely to allow water infiltration.

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Asphalt Materials Shines the Spotlight on Sustainability

As The Heritage Group continues to expand capabilities and investments in the sustainability space, the Asphalt Material’s team is also focused on sustainability in a number of different areas, this article is focused on CCPR or Cold Central Plant Recycling.

CCPR is the process in which the asphalt recycling takes place at a central location using a stationary cold mix plant and an existing stockpile of RAP or reclaimed asphalt pavement.

Why is CCPR a Sustainability Initiative?

Aggregate and oil resources are not infinite and current conventional remove-and-replace approaches to construction projects is unsustainable and not always budget-friendly. CCPR is a modern, yet time-tested approach. It has helped agencies complete more projects within the same budget, or in many cases with reduced dollars versus budget without sacrificing the structural integrity of asphalt pavements.

By reducing energy usage during the processing, CCPR is an ideal choice for road construction projects. There is a smaller carbon footprint and reduction in greenhouse gases because of the significant reduction in trucks exporting and importing materials to and from the site.

RAP is a Valuable Asset!

Agencies paid for the initial construction materials for an existing asphalt pavement. With CCPR, agencies are able to reuse those materials and stretch their budget dollars. When roads last longer, infrastructure funds go further.

CCPR Can be Less Expensive

CCPR is less expensive than conventional maintenance, reconstruction, or new construction methods. Rehabilitating a road with an engineered emulsion additive is less expensive than producing a virgin hot mix made from completely new materials. Typical overall project cost savings can be 25% or more.

Nate Jenkins (AMI Sales Representative) and Tim Zahrn (Specialty Products Area Manager) collaborate on a number of recycling projects around the state of Indiana. They also draw on the expertise of The Heritage Research Group, specifically team members like Megan Yount, and Zach Robinson. A few of their insights are seen below.

CCPR is a green approach that is not only environmentally friendly, but is often economically advantageous to agencies. – Tim Zahrn, Specialty Products Area Manager for Asphalt Materials, Inc.

CCPR gives an agency the ability to remove existing asphalt pavement and fix the underlying pavement issues, reusing the RAP in the new pavement structure. – Megan Yount, Heritage Research Group.

CCPR is placed at ambient temperatures and the mixing plant is typically located in close proximity to the project.  This decreases excessive hauling and utilizes a lower amount of virgin material in comparison to some other alternatives. – Jason Wielinski, Asphalt Institute.

If an agency needs to remove the existing pavement structure, RAP, it makes sense to reuse the material that the agency already owns. – Nate Jenkins, Asphalt Materials Inc. Sales Representative.

RAP has value and can be used by an agency for a number of different things, but can be very valuable when used in a CCPR or other pavement recycling processes. – Zach Robinson, Heritage Research Group.

Show below are a number of different pictures taken at different stages of a CCPR project. In addition, you may be interested in watching a short video of CCPR here: Video Link.

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