The pursuit of pavement smoothness has evolved from a quality benchmark into a direct revenue driver for asphalt paving contractors. State departments of transportation increasingly offer financial incentives for superior ride quality, measured by profilograph readings, making equipment decisions a strategic business consideration. For contractors evaluating fleet upgrades, understanding How to Select Asphalt Paver Screeds for Optimal smoothness directly determines their ability to earn these bonuses. Chester Bross Construction Company of Hannibal, Missouri, provides a compelling example of how a calculated investment in modern paving technology translated into consistent maximum smoothness bonuses on a challenging interstate project.
Why Smoothness Bonuses Are Reshaping Equipment Investment Decisions
State transportation agencies across the United States have adopted incentive-based smoothness specifications that reward contractors for exceeding minimum ride quality thresholds. These programs, often tied to profilograph or inertial profiler measurements, can add significant revenue to a project when a contractor consistently delivers a smooth pavement surface.
The Financial Case for Premium Equipment
Chester Bross Construction Company was not planning to make major capital investments during a challenging business year. However, when the company tested a Roadtec RP-190e rubber-tired asphalt paver on an active project, the ride numbers were substantially better than what the contractor achieved with older equipment. According to Mike Bross, owner and vice president of operations, the decision to purchase was made strictly on the performance observed during the demo trial.
If we can increase productivity and get results achieving or approximating 100 percent bonus, then the purchase of a new machine becomes a no brainer.
Mike Bross, Chester Bross Construction Company
The economics are straightforward. When a paver consistently delivers smoothness that earns maximum incentive payments, the machine effectively helps pay for itself over the course of several projects. Contractors who equip their fleets with technology capable of meeting stringent specifications position themselves to win more work while earning higher margins on each job.
How Smoothness Is Measured on Modern Projects
Most state DOTs use profilograph readings or inertial profiling systems to quantify ride quality. The profilograph measures surface irregularities and produces a profile index expressed in inches per mile. Lower values indicate a smoother pavement. Contractors who achieve readings below specified thresholds earn bonus payments that can range from 2 to 10 percent of the paving contract value. The stakes are high enough that equipment selection has become a central element of project planning.
Critical Technologies That Enable Superior Ride Quality in Modern Pavers
Modern highway-class asphalt pavers incorporate several key technologies that directly influence smoothness outcomes. The Roadtec RP-190e, for example, underwent a major redesign that integrated multiple systems working together to deliver consistent mat quality.
Material Flow Control Systems
Material handling from the hopper to the screed determines how uniformly asphalt is placed. Uneven material delivery creates density variations that show up as roughness in the finished surface. The RP-190e incorporates several features to address this:
- Anti-segregation design that prevents the larger aggregate particles from separating during material transfer, ensuring a consistent mix across the entire mat width.
- Electric flow gates that provide precise, responsive control over the amount of material entering the auger chamber, eliminating the guesswork of manual gate adjustment.
- 18-inch hydraulic tunnel extensions that maintain proper material flow at the edges of the paver, where segregation and surface irregularities most commonly occur.
- Independent auger and conveyor operation that gives the operator complete control over material distribution, allowing fine-tuning for changing conditions without affecting delivery rate.
Screed Design and Setup Flexibility
The screed is the final point of contact between the paver and the asphalt mat, making its design critical to smoothness outcomes. The RP-190e features a 10-foot main screed with extension wings that accommodate varying lane widths. On the I-55 project, a five-foot extension wing on the right side and a four-foot extension wing on the left allowed the crew to pave a consistent 12-foot-wide lane.
Contractors looking to understand the nuances of screed selection can explore How Asphalt Paving Contractors Meet Stricter Smoothness Specifications with properly configured screed systems. The right screed setup reduces the need for constant operator intervention, which translates directly into more consistent mat quality.
Powertrain and Operator Station Upgrades
Beyond the material handling systems, modern pavers benefit from improved powertrain and ergonomics that contribute to smoothness:
- Tier 4i Cummins QSB 6.7 engines rated at 230 hp provide consistent power delivery without the fluctuations that can cause surging or hesitation in the paving speed.
- Heavy-duty offset conveyor chains with chromium carbide floor plates that drop in without bolts reduce maintenance downtime and ensure reliable material delivery.
- Updated dual operator stations with hydraulic-pivot consoles and selectable seat positions improve visibility and control, allowing operators to maintain optimal positioning throughout the paving pass.
Technology Comparison: Modern versus Older Pavers
| Feature | Modern Paver (RP-190e) | Older Conventional Paver |
|---|---|---|
| Material flow control | Electric flow gates, anti-segregation augers | Manual gate adjustment |
| Screed control | Hydraulic extensions, automated slope control | Manual mechanical adjustments |
| Operator interface | Dual hydraulic-pivot stations with digital displays | Single station with analog gauges |
| Engine emissions tier | Tier 4i (230 hp, consistent power) | Earlier tier, variable power delivery |
| Conveyor system | Heavy-duty offset chains, boltless chromium floor plates | Standard chains, bolted floor plates |
| Auger-conveyor independence | Independent operation for precise material tuning | Linked operation, limited fine control |
| Setup time | Quick morning startup with minimal adjustments | Extended warmup and calibration required |
| Typical bonus achievement | Consistent maximum bonus | Partial bonus or base pay only |
Proper operator training is essential to leverage these technologies effectively. As highlighted in Training and Advanced Paver Controls Deliver Smoothness Bonuses, crews that understand how to dial in modern control systems consistently outperform those relying on outdated techniques.
Real-World Performance: The I-55 Superpave Project
Project Scope and Challenges
One of the first major projects for Chester Bross with the new Roadtec RP-190e was a 14-mile, four-lane stretch of Interstate 55 in Scott County, Missouri. This $7 million Missouri DOT project required placing asphalt over an existing worn concrete highway surface. The scope of work was substantial:
- 120,000 tons of asphalt total, with 70,000 tons for the base layer and 50,000 tons for the finish lift.
- Two lifts: a two-inch base course to smooth the uneven concrete surface, followed by a 1.75-inch stone-mastic asphalt (SMA) finish lift.
- Severe weather delays in the spring pushed the start date to late September, requiring completion by the second week of November before winter weather arrived.
- Accelerated schedule compressed what would normally be a longer timeline into less than two months of production.
How Modern Equipment Saved Time and Improved Quality
The eight-member crew worked 16 to 18-hour days to meet the tight deadline. Site superintendent Phillip Dowell credited the RP-190e with making this accelerated schedule achievable. According to Dowell, the machine saved at least two days of production compared to what the crew could have achieved with older equipment.
Key factors that contributed to the productivity gains included:
- Faster paving speeds without sacrificing quality, allowing the crew to place more tonnage per shift.
- Quick morning setup that reduced non-productive time at the start of each day.
- Consistent automatics that required minimal adjustment throughout the shift, keeping the paver at optimal settings.
- Reliable material flow from the anti-segregation system and electric flow gates, reducing stoppages for manual adjustment.
Material transfer vehicles can further enhance these efficiencies. For contractors interested in optimizing the material delivery side of their operation, How Shuttle Buggy Material Transfer Vehicles Help Contractors earn smoothness bonuses by maintaining continuous, uniform material feed to the paver.
Practical Strategies for Achieving Maximum Smoothness on Complex Projects
Matching Lift Design to Pavement Conditions
The I-55 project demonstrates the importance of lift design in achieving smoothness. The two-inch base lift was designed specifically to smooth out the uneven surface of the old concrete highway. This deeper initial lift absorbed the existing irregularities, creating a consistent platform for the finish course. The 1.75-inch SMA finish lift then provided both the final surface smoothness and long-term durability.
SMA requires careful handling because of its higher binder content and stone-on-stone aggregate structure. The material is stickier than conventional asphalt, which helps it adhere better to the base layer. However, this same stickiness demands consistent paver operation to prevent tearing or surface imperfections.
Crew Coordination and Setup Protocols
Dowell noted that the RP-190e was easy to set up in the morning. With newer technology, the machine automatics deliver exacting results without requiring regular adjustments. This reliability reduced operator fatigue during the long shifts and kept the paving operation moving at a steady pace.
Best practices for crew coordination on high-stakes smoothness projects include:
- Establishing a standardized morning startup checklist that covers screed preheating, sensor calibration, and material flow verification.
- Maintaining consistent paver speed throughout each pass, as speed fluctuations create ripple effects in the mat surface.
- Monitoring material temperature at the screed to ensure it remains within the specified range for compaction.
- Communicating between the paver operator and the roller operators to coordinate passes without delays that allow the mat to cool unevenly.
The Value of Working with State Inspectors
MoDOT inspectors were pleased with the finished smoothness of the I-55 section and the fact that the work was completed ahead of schedule. The project aligned with MoDOTs initiative to smooth out much of the states pavement, which is projected to improve annual fuel economy in Missouri by 2.4 percent. Building a reputation for delivering smooth, on-schedule work helps contractors secure favorable relationships with agency inspectors and improves their standing in future bid evaluations.
As Dowell summarized, the project achieved three critical objectives: the road was made exceptionally smooth, the work was completed ahead of the accelerated schedule, and the operation generated strong financial returns. This combination of quality, speed, and profitability is the benchmark that modern paving contractors should target when making equipment and training investments.