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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