Accelerated Pavement Testing Overview

• Industrial companies/research labs need to test new road surfaces/building methods for long-term durability
• Roads must last decades - need to simulate hundreds of thousands of vehicles over years without actual time investment
• Solution: "accelerated pavement testing facility" - only few exist worldwide

French Fatigue Carousel Facility

• Built 1984, located in west France
• One of world's largest accelerated pavement testing facilities
• Central tower with hydraulic motors powering machine
• Four arms with outer wheels that load pavements
• Ring length: 120 metres
• Test section width: 6 metres
• Simulates 10-20 years real road traffic in few months

Testing Applications & Evolution

• Originally used to validate French pavement materials
• Current new applications:
  • Bio-binders testing to replace bitumen (petroleum will disappear)
  • Electric vehicle road charging systems research

Technical Specifications & Capabilities

• Maximum speed: 100km/h
• Usual testing speed: 70km/h (safety margin from maximum)
• Load range per single axle: 4.5-8.5 tonnes
• Can overload pavement to accelerate deterioration
• Wheel configurations: single wheels, dual wheels, two axles, three axles
• Lateral wheel movement capability to reproduce real traffic effects
• 1000-horsepower engine powering system

Instrumentation & Monitoring

• Soil instrumentation:
  • Displacement transducers
  • Vertical strain transducers for vertical displacement measurement
• Bituminous layer instrumentation:
  • Strain gauges (most common)
  • Temperature sensors (critical for pavement response)
  • Accelerometers/geophones for vertical acceleration measurement

Facility Infrastructure

• Three different circular test tracks
• Carousel can be disassembled and moved between tracks
• Parallel testing capability: one track testing while another rebuilt
• Track sectioning allows multiple simultaneous tests
• One watertight track for wet/soaked ground pavement testing

Testing Duration & Process

• Tests run continuously for months
• Constant rotation with wheels at up to 100km/h
• Years of pavement stress/damage compressed into weeks
• Takes minutes to reach operating speed

Testing Limitations & Validation

• Cannot control climate conditions (accelerated test limitation)
• Cannot simulate bituminous material aging (materials become more brittle over time)
• Validation method: include reference section with known material
• Comparison with classical materials using correction coefficients
• Results adapted to real conditions through coefficient adjustments

Real-World Testing Necessity

• 21st century computer modeling/simulation requires real-world data foundation
• Public safety and billion-euro infrastructure projects demand physical testing
• No substitute for building real test sections for validation