How Kraton and NCAT Prove What is Possible with HiMA Technology

挑戦

Thin Pavements Without Compromise

Designing thin pavements that resist rutting or cracking is well understood. Designing pavements that do both, especially at reduced thickness, is far more difficult.

As pavement structures become thinner, traditional polymer-modified binders often force designers into tradeoffs:

• Stiffer mixtures improve rut resistance but increase cracking risk
• More flexible mixtures reduce cracking but deform under traffic
• Reduced thickness amplifies both risks

Seeking thinner pavements to lower costs, reduce emissions, and minimize traffic disruptions, the question is clear: Can thin pavements deliver long-term reliability on high-traffic roads?

解決策

The NCAT N7 Test Section with HiMA

To answer that question, Kraton worked with NCAT to construct and evaluate the N7 test section at NCAT’s full-scale accelerated pavement testing facility at Auburn University in Alabama. NCAT is globally recognized for its ability to simulate decades of truck traffic in a controlled, high-speed environment.

The N7 test section was intentionally designed to challenge conventional assumptions.

Pavement Structure and Materials:

• Three layers of asphalt pavement constructed over 14 cm (5.5 in) of aggregate base
• Total asphalt thickness of 14.6 cm (5.75 in)
• Approximately 18% thinner than the conventional control section

Layer Details:

• Wearing course: 3.2 cm (1.25 in), with a 9.5 mm NMAS dense graded mixture
• Base course: two layers, which were each 5.7 cm (2.25 in) with a 19 mm NMAS dense graded mixture
• All asphalt layers used Kraton HiMA bitumen technology

Production and Placement:

• HiMA mixtures produced at 174°C (345°F)
• Compaction temperatures ranged from 115 to 147°C (240 to 295°F)

The control section used a conventional polymer binder and a thicker pavement structure, reflecting typical industry practice.

Measured Performance Under Real Traffic

Both sections were subjected to 20 million equivalent single axle loads (ESAL) over five years, simulating heavy truck traffic well beyond what many pavements experience in service.

The results were decisive:

• The HiMA N7 section exhibited 70% less rutting than the control section
• No bottom-up fatigue cracking was observed in the HiMA section
• The control section showed fatigue cracking across 18% of the surface area

These outcomes demonstrate that a thinner pavement, when engineered with the right material technology, can outperform a thicker conventional design in both deformation resistance and fatigue life.

影響

Why This Matters Beyond the Test Track

The NCAT N7 results provide more than laboratory validation. They offer practical, data-driven confidence for roadway owners considering thinner pavement strategies.

Key Benefits Observed:

• Longer service life potential with reduced thickness
• Improved reliability under heavy traffic
• Reduced material usage and associated emissions
• Strong life cycle value compared to conventional PMB solutions

By enabling thinner pavements that last longer, HiMA technology supports goals related to sustainability, economic efficiency, and network reliability.