September 24, 2021

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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September 22, 2021

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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September 17, 2021

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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July 12, 2021

Success Story: CMS in Iowa

Cationic Emulsions are made up of three major classifications of emulsion grades: rapid-setting, medium-setting, and slow-setting. The terms “rapid,” “medium,” and “slow” relate to the amount of time it takes for the emulsion to cure and the amount of mixing that can be performed before the emulsion breaks. Emulsions that allow for the longest mixing times generally take the longest to cure, while emulsions that allow for very little mixing time are those that set and cure most rapidly.

Chemical surface-active agents, serving as emulsifiers, are classified by the electrochemical charge that is attained when they dissociate in a water solution. In the case of cationic emulsions, the chemical charge is positive. The chemical type and quantity of surface-active agents used in the manufacturing process governs the properties of the emulsion and in what applications the resulting asphalt emulsion can be used.

As many people know, Asphalt Materials, Inc. is made up of a large family of companies. One of these companies, Bituminous Material and Supply, with plant locations in Tama and Des Moines, Iowa, was approached by Denco Construction regarding an interest in using scrub seal in Iowa. This is an emulsion seal that is not often seen in Iowa. A scrub seal is an application that is very similar to a chip seal treatment. The only difference is that the asphalt distributor pulls a broom sled that houses a series of brooms placed at different angles. These brooms guide or “scrub” the emulsion into cracks to help ensure the road’s surface is sealed.

Testing

The scrub seal is a process by which asphalt emulsion is applied to a pavement surface by an asphalt distributor. The emulsion is scrubbed into the cracks and voids with a broom before a layer of aggregate is applied over the asphalt. The scrub seal is then rolled with a pneumatic tire roller and is usually ready for controlled traffic in 1 hour or less. The scrub seal process is intended to rejuvenate dry, oxidized, and cracked asphalt pavements in lieu of a micro-surfacing, chip seal or asphalt overlay. This process was tested on roads that interested counties offered as a demo. Below, you’ll find images that were taken during the testing process.

Results

The evaluation of the demo roads showed success, and Bituminous is now focused on sand applications. Denco Construction purchased a sand spreader during the winter season to fulfill the county’s request.

According to Chris Aldama, Plant Manager at Bituminous, “It’s still a pretty fresh process. Denco was able to take approximately 10,000 gallons at the end of June, but needs to make adjustments on sand suppliers. Once sand quality is finalized, I’m confident in the long term success in this area and beyond.”

To learn more about the process, feel free to watch this video:

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