Minnesota took a major step forward in pavement preservation this summer with its first application of AMIGUARD™ Rapid Penetrating Emulsion Rejuvenator (RPE-R) in Carlton County. As agencies across the country look for smarter interventions to extend pavement life, this project signals a significant milestone in the shift toward proactive strategies that protect infrastructure early on.
Innovating in Carlton County
Carlton County is no stranger to evaluating new techniques in the pavement preservation category. In 2024, the county applied its first use of Void Reducing Asphalt Membrane, (VRAM) on 22nd St. and continued using J-Band®, the premier VRAM, on additional roadways in 2025.
Building on this experience, the county was approached in May 2025 to pilot AMIGUARD RPE-R, an engineered, bio-oil-based emulsion rejuvenator designed to chemically modify existing asphalt to offset the effects of aging. After evaluating two candidate locations, the county selected the same stretch of 22nd St. for the RPE-R demo.
AMIGUARD RPE-R: Offsetting Effects of Aging
AMIGUARD RPE-R is designed with a chemical package that helps it permeate below the surface, delivering rejuvenating agents into the pavement quickly and thoroughly. The formula behind RPE-R allows it to break surface tension — that’s the reason the liquid can move into and through smaller, interconnected voids within the pavement. Rather than only sealing the surface like traditional fog seals, RPE-R fills voids and offsets the effects of aging by chemically changing existing asphalt. The rejuvenating oils used to produce AMIGUARD RPE-R are engineered to minimize or eliminate the need for sanding the treatment once the emulsion is dried. This creates a truly “single pass” application with no need to return for sweeping or sand removal.
Asphalt Materials developed its AMIGUARD Rapid Penetrating Emulsion products around the core principle of preserving pavement early and effectively. Applying RPE-R in the first few years of a pavement’s life, when the binder is still relatively fresh but beginning to show properties of aging, can significantly extend service life, delay the onset of cracking and lock-in pavement performance before notable distress.
This strategy is rooted in the concept of addressing rheological age, emphasizing the importance of rejuvenating pavement early in its lifecycle. Rheological impacts refer to the changes in an asphalt binder’s properties, like stiffness and brittleness, due to the effects of aging. While aging can’t be undone, its effects can be offset.
That’s why the Carlton County demo on 22nd St. North was so timely. In its second year of service, the road was at an ideal stage for rejuvenation. Early in its life, pavement has a low rate of change in quality, but after several years, change accelerates, and quality begins to rapidly decline. By selecting RPE-R for this application, the county demonstrated a forward-thinking approach to road management: building road resilience starts with choosing the right treatment on the right road at the right time.
Site Evaluation & Planning
A site evaluation in June 2025 confirmed the pavement was in good condition, with no observed distress or cracking, ideal for a rejuvenator application.
Existing surface condition prior to application
This half-mile, two-lane urban roadway is adjacent to Cloquet Senior High School and includes parking and bus lanes, features six intersecting streets and roughly 30 driveway aprons, including one commercial business. With an average daily traffic (ADT) of approximately 1,000 vehicles in the summer and doubling during the school year, timing and minimal disruption were critical considerations of the project.
The county’s objectives for the RPE-R demo were clear:
- Initiate early preventative maintenance on newly paved surfaces
- Pilot a new treatment with minimal disruption to residents and businesses
- Preserve existing pavement markings without the need for repainting
Project Details
- Location: 22nd St. North between Washington Ave and Prospect Ave
- RPE-R Supplier: AMI Portage Plant
- Contractor: Scott Construction
- Date Applied: August 27, 2025
Application Details
- Target Application Temp: 160°F
- Target Rate: 0.055 gal/SY
- Weather: 57°F ambient, 65°F pavement, cloudy to partly cloudy, light winds
Application began at 8 a.m. on the southbound lane (moving northbound), followed by the northbound lane at 8:45 a.m. Carlton County opted to close the entire roadway for the application, maintaining driveway access while redirecting cross-street traffic. The entire roadway was reopened to traffic by 12 p.m. No sanding was required.
The material sprays a light khaki color but dries to a semi-transparent finish.
Despite the setting with numerous driveways, intersections and existing markings, the project was executed smoothly. The team completed the work with minimal impact to the driving public by avoiding peak traffic and school-related congestion. High constructability of AMIGUARD RPE-R shows exceptional prospect to be scaled to similar environments and serve as a model for future success in this region.
With a successful demo under its belt, Carlton County is showing interest in the potential of future applications.
AMI Specialty Products Area Manager, Jim Romanik, was on site for the application to provide support and ensure that the county’s goals for the project were achieved. He shared his thoughts on the project’s success:
“The AMIGUARD RPE-R application in Carlton County went exceptionally well. The product performed just as we hoped — quick application, minimal disruption to traffic and strong early-life rejuvenation. It’s exciting to see a forward-thinking agency embrace this kind of proactive pavement preservation. I believe this success will open the door for more agencies across Minnesota to explore AMIGUARD RPE-R as a smart, scalable solution to extend pavement life and protect infrastructure investments.”
The material’s semi-transparent dried finish allows existing paint markings to show through.
A follow-up site visit and core sampling post-application will contribute to the evaluation of long-term performance.
Rejuvenating Asphalt One Road at a Time
This project not only highlights Carlton County’s commitment to proactively maintaining infrastructure but also the growing interest in rejuvenator technologies nationwide.
Pavement preservation techniques like AMIGUARD RPE-R are gaining traction as a smart solution for counties interested in protecting their investments early. And when combined with VRAM, such as on 22nd St. North, durability significantly increases, further reinforcing overall strength, in turn increasing the life of the road. By targeting the right roads with the right treatments at the right time, road managers can reduce long-term maintenance costs and extend serviceable roads for their communities.
Want to know if AMIGUARD rapid penetrating emulsions might be the right fit for your next pavement project? Reach out to our team at marketing@asphalt-materials.com to schedule a road evaluation or discuss treatment options.
