Void Reducing Asphalt Membrane (VRAM) Expected to Prolong Pavement Lifespan

Item #: 20240044

CONTACTS

Implementing Organization: Region 4, Pavements and Materials
Implementation Lead: Jared Dastrup
Development Team: Jared Dastrup, Cody Marchant, Mike Blotter, Howard Anderson, Jason Simmons
- Contractor - Shannon Davis, Western Rock
- Subcontractor (that applied the VRAM) - Spencer Foster, Z&Z Seal Coatings
- RE Consultant - Lyndon Friant, Jone & Demille
Article Written By: Craig Hebbert
Innovation Council Liaison: Craig Hebbert
Innovation Team Coordinator: Quinten Klingonsmith

STATUS

Implementation Date: June 1, 2024
Adoption Status: Initial test completed. Verification underway.
Adoptability Note: What future project could benefit from VRAM?

APPLIES TO

Topic: Construction Practices
Organization(s): Central Maintenance / Facilities Management, Central Materials, Central Preconstruction, Performance and Asset Management, Planning, Region 1, Region 2, Region 3, Region 4, Research and Innovation, Structures
Job Role(s): Construction Engineer, Materials Engineer, Transportation Technician
Tags: highway transportation, capital productivity, infrastructure preservation, economic benefits, expenses, expenditures, value of time, products, civil engineering, materials science, asset management, construction, design, maintenance, asphalt, pavement, VRAM, SMA, Stone Matrix Asphalt, quality of life, user benefits

PROBLEM

Potholes and premature cracking occur along the longitudinal joint in Stone Matrix Asphalt (SMA) pavements due to air voids along the joint. These air voids result in lower compaction and more pervious pavement that is susceptible to moisture intrusion and freeze-thaw deterioration.

CHANGE

Applying a void-reducing asphalt membrane (VRAM) at the location of the future longitudinal joint before paving helps mitigate this problem. A truck with an inline spray bar applies a heavy, polymer-modified, fluid asphalt membrane approximately 5/32 of an inch thick and 18 inches wide. The VRAM band cures within 15 to 30 minutes, at which point it can be paved. When the contractor paves, the heat from the new asphalt melts the VRAM and wicks the VRAM from the bottom-up into the new asphalt, filling many of the air voids along the construction/longitudinal joint (see Diagram 1).

To verify its effectiveness a test section was created by placing a VRAM on about half of the test project and the other 5 miles of the project were paved traditionally without a VRAM. Cores taken from the VRAM section showed greater longitudinal joint density compared to those taken from the non-VRAM control section.

RESULT

It is anticipated that reducing air voids with VRAM will extend the cracking performance and life of the longitudinal joint by up to 4 to 5 years.

Next Steps: The next steps are to scan the longitudinal joint with the rolling density meter to compare the densities of the two sections (with vs without VRAM) and analyze the cores to determine the effectiveness of the VRAM, i.e., how far up into the cores the VRAM migrated.

We will monitor the test section and compare the results over time to determine the effectiveness of the VRAM in preventing longitudinal cracking. Once the effectiveness of the VRAM is verified, other projects will be evaluated and appropriate candidate projects will be selected for VRAM application.

Diagram 1.

VRAM being sprayed prior to paving.

IMPACT

BETTER MOBILITY

Fewer repairs require less maintenance-related congestion and lane closures

GOOD HEALTH

Smooth crack and pothole-free roads improve safety

CONNECTED COMMUNITIES

STRONG ECONOMY

The additional cost is more than recouped by fewer repairs, a longer lifespan, and greater mobility

EFFICIENCIES*

$335,775 cost avoidance calculated by not having to do a mill and fill of the longitudinal joint at the time the pavement requires its first chip seal. This estimate is just for savings along the 2.5-mile portion of the test road and would be enormous as VRAM is more widely used along hundreds of miles of roadway.

*Benefits are estimated net of initial and ongoing expenses. Savings are averaged over the expected benefit life of the innovation. See details.

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