When a road-building company with more than 150 years of history adopts a new technology, the industry pays attention. Barrett Paving Materials, Inc., a division of Colas, Inc., has been at the forefront of asphalt innovation since 1903, when it developed Tarvia, a roofing tar treatment that revolutionized early roadway construction. Today, the company is leading the charge in warm mix asphalt production using water-injection foaming technology. For contractors seeking the Road to Management Excellence Building a Stronger construction operation, understanding these advances is essential.
The Evolution of Warm Mix Asphalt Technology
From Hot Mix to Warm Mix
Traditional hot mix asphalt (HMA) requires production temperatures between 310 and 320 degrees Fahrenheit. These high temperatures consume significant energy, generate substantial emissions, and create challenging working conditions for paving crews. Warm mix asphalt (WMA) technology addresses each of these concerns by allowing producers to lower mixing temperatures by 50 to 90 degrees Fahrenheit while maintaining pavement quality.
Several approaches to warm mix production have emerged over the past two decades. The three main categories include:
- Organic additives such as waxes blended into the liquid asphalt cement to reduce viscosity at lower temperatures
- Chemical additives including proprietary surfactants and emulsifiers that improve coating and workability
- Water-injection foaming which introduces a controlled amount of water into the hot binder to create a foaming action that expands the asphalt volume and improves aggregate coating
Why Barrett Chose Water-Injection Foaming
Barrett Paving began experimenting with warm mix technology several years ago at its Jamesville, New York plant. The facility, which has operated since 1927 and now houses both batch and counterflow drum mix plants, initially tested warm mix binder additives including wax blends and proprietary binders. While these products successfully lowered production temperatures, they came with a significant drawback.
William “Bill” Lallier, plant manager for Barrett’s N.Y. Central Region, noted the fundamental economic challenge: there is an additional cost per ton to use chemical or wax additives. With a vision to expand warm mix production across multiple plants, Barrett evaluated three different manufacturers offering water-injection foaming systems. The company selected the Terex Roadbuilding warm mix system for three primary reasons: ease of installation, compact design, and compatibility with any drum mix plant in the Barrett fleet.
How Water-Injection Foaming Works
System Components and Operation
The Terex warm mix asphalt system comprises two main components that integrate directly into an existing asphalt plant setup.
- Expansion chamber installed directly into the plant’s existing liquid AC line. This chamber mixes water with hot binder to create a foaming action. The foamed asphalt then flows through the existing AC line into the drum, where it thoroughly coats the aggregate.
- PLC/water skid package that controls system operation through the plant’s existing controls. The pump precisely meters a predetermined amount of water to the expansion chamber based on a percentage of the binder’s mass weight.
This straightforward design allows producers to switch between hot mix and warm mix production without major plant modifications. The system can be installed on virtually any drum mix plant, making it an attractive option for contractors with multiple facilities.
Performance Benefits at the Plant
Barrett installed the system on its existing Terex Magnum E400 counterflow plant, a 400-ton-per-hour facility. The results demonstrated measurable improvements across several critical metrics:
| Performance Metric | Hot Mix Asphalt | Warm Mix (Foamed) | Improvement |
|---|---|---|---|
| Production temperature | 310-320 degrees F | 285-290 degrees F | 25-30 degree reduction |
| Maximum RAP content without blue smoke | 40 percent | 50 percent | 10 percent increase |
| Estimated fuel consumption | Baseline | 10-15 percent reduction | Lower operating costs |
| Emissions at production temperature below 300 degrees F | Standard levels | Reduced emissions | Improved environmental compliance |
The ability to increase reclaimed asphalt pavement (RAP) content from 40 to 50 percent without generating blue smoke represents a significant sustainability advance. Higher RAP usage reduces demand for virgin aggregate and binder, lowering both material costs and environmental footprint. The estimated 10 to 15 percent fuel savings further improve the economic case for water-injection foaming technology.
Regulatory Approval and Quality Verification
The New York State DOT Approval Process
Before Barrett could use warm mix on New York State Department of Transportation projects, the Terex system had to undergo one of the most rigorous approval processes in the country. State officials requested and tested warm mix asphalt samples covering both virgin and RAP mix designs, using both PG 64-22 and PG 70-22 binders.
The approval process examined every aspect of the technology:
- Calibration of the water pump and metering accuracy
- Water injection rates and their effect on binder performance
- Technical documentation on how the foaming technology operates
- Experience and feedback from other states using the system
- Lay down and compaction procedures for warm mix placement
Terex Roadbuilding partnered closely with Barrett to supply all the information the state required. In the summer of 2010, the Terex warm mix asphalt system became the first water-injection foamed warm mix technology approved for use on New York State DOT projects.
Quality Testing Protocols
Proper Building Wrap Selection Installation and Performance of Weather systems require rigorous testing, and the same principle applies to warm mix asphalt. The NYSDOT testing regimen included verification that foamed asphalt mixes met the same performance specifications as conventional hot mix. The approval set a precedent that other states would follow, establishing water-injection foaming as a viable production method for public infrastructure projects.
Field Performance, Economics, and Industry Impact
Project Overview: Highway 481 Resurfacing
Barrett’s first warm mix project specified by Region 3 of the NYSDOT was a mill-and-fill resurfacing of Highway 45, straddling Fulton and Oswego Counties. The project specifications demanded high-quality work on a busy divided highway.
| Project Parameter | Specification |
|---|---|
| Project length | 4.9 miles |
| Lane configuration | Two 12-foot lanes per direction plus 10-foot and 4-foot shoulders |
| Total lane-miles resurfaced | Nearly 20 lane-miles |
| Total warm mix tonnage | 22,000 tons |
| Mix type | 9.5 mm top course with PG 64-22 binder |
| RAP content | 20 percent |
| Compacted thickness | 2 inches |
| Required density | 92 to 97 percent |
Barrett’s crews milled the top two inches of the oxidized asphalt surface before placing the fresh warm mix. The Magnum E400 plant in Jamesville produced the mix, which had to be transported more than 30 miles to the jobsite with a one-way transit time of approximately one hour.
Compaction and Workability Advantages
Despite the long haul from plant to jobsite, the warm mix retained excellent workability. Mix temperatures at production were between 285 and 290 degrees Fahrenheit compared to the 310 to 320 degrees that would have been required for hot mix. With tarped loads, the material arrived at approximately 280 degrees Fahrenheit, showing minimal temperature loss during transit.
Donald Williamson II, project superintendent for Barrett’s N.Y. Central Region, reported that the pavement laid exceptionally well when the mix was at a steady 275 to 285 degrees behind the screed. The crew achieved improved compaction with the breakdown roller, requiring fewer vibratory passes to reach the specified density. The finish roller began its passes in the 250 to 260 degree range, and crews achieved the required 92 to 97 percent density at approximately 230 degrees Fahrenheit.
Worker and Environmental Benefits
Wesley Hood, construction manager for Barrett’s N.Y. Central Region, emphasized that foamed asphalt stays workable longer than conventional hot mix. This extended workability window gives paving crews more time to achieve proper mat density and surface quality. Beyond operational advantages, the lower temperatures create a better working environment for crews who no longer must work in the intense radiant heat of a traditional hot mix mat.
The reduction in emissions from both the plant and the paving operation represents a meaningful improvement for communities near asphalt facilities and highway projects. For road construction firms evaluating their equipment and methods, understanding Highway and Bridge Construction Equipment Specialized Machinery for modern paving operations is critical to staying competitive.
Cost Savings and Structural Implications for the Industry
The economic advantages of water-injection foaming extend beyond simply replacing expensive chemical additives with water. Lower production temperatures reduce fuel consumption at the plant, while the ability to increase RAP content reduces raw material costs. Reduced emissions may also help producers comply with increasingly stringent environmental regulations without expensive add-on control equipment.
As more state DOTs approve water-injection warm mix technology, the asphalt industry is likely to see a fundamental shift in production practices. The combination of lower costs, reduced environmental impact, and improved working conditions makes a compelling case for broader adoption. Plant operators and paving crews who master this technology will have a competitive advantage in bidding for both public and private sector work. Upgrading aging infrastructure with modern materials and methods parallels the principles discussed in Building Retrofitting Structural Strengthening Methods for Seismic Upgrades, where innovative approaches deliver better performance at competitive costs.
Key Takeaways for Contractors
- Water-injection foaming eliminates the per-ton cost of chemical or wax additives while achieving comparable temperature reductions of 50 to 90 degrees Fahrenheit
- The technology enables higher RAP content without emissions penalties, improving both sustainability and material cost efficiency
- Fuel savings of 10 to 15 percent are achievable at the plant level
- Extended workability of foamed asphalt improves compaction outcomes and gives crews more time to achieve density specifications
- Reduced emissions and lower mat temperatures create safer, more comfortable working conditions for paving crews
- The system can be retrofitted to existing drum mix plants with minimal modification, making adoption accessible to producers with established facilities
Barrett Paving’s successful deployment of water-injection warm mix technology on a major NYSDOT project demonstrates that the approach is ready for mainstream adoption. With 22,000 tons of warm mix placed on Highway 481 meeting all specification requirements, the project provided real-world validation of laboratory and theoretical benefits. As more states follow New York’s lead in approving foamed asphalt technologies, contractors who invest in understanding and implementing these systems will be well positioned for the future of road construction.