Dear participant hello. I'm Pierre Hornych, from IFSTTAR. It's a pleasure to meet you again for this new technical session. This video presents the IFSTTAR accelerated pavement testing facility. This facility, also called the IFSTTAR carrousel, is used to test pavements in full scale, under heavy vehicle loads. I will first explain the interest and principles of full scale accelerated tests, and then present the characteristics of the IFSTTAR carrousel. Finally, I will present some examples of tests. The behavior of pavements is complex, and predicting their long term behavior using mechanical models- still remains a challenge, for several reasons: Pavements are multilayer structures, consisting of different materials. This was detailed in the previous video I presented. They are subject to complex moving wheel loads. Their behavior is strongly affected by climatic variations, (temperature, moisture content). They are designed for long service lives, generally 20 to 30 years. For these reasons, full scale tests are needed, to validate new pavement materials, and new types of structures. Such tests can be performed on real roads, but this is very time consuming, because several years are generally necessary before the pavement starts to deteriorate. Accelerated tests present the advantage of accelerating the traffic, so that the pavement can be tested up to failure, in a few months. In addition, the pavement is generally instrumented, to monitor its behavior under traffic. The IFSTTAR carrousel is one of the largest pavement testing facilities in the world. It is a circular facility, consisting of a center motor unit, and four arms carrying the wheel loads. The diameter of the arms is 40 meters and the length of the test track is 120 meters. The maximum operating speed is 100 kilometers per hour. At high speed, the carrousel can apply approximately 1 million heavy vehicle loads per month. This represents the traffic supported by a medium-traffic road (with 150 heavy vehicles per day) during 20 years. So, for this road, the traffic is accelerated by a factor of 240! The IFSTTAR carrousel is a mobile facility. The site comprises three test tracks, and the carrousel can be moved from one track to another, in less than one week. It is thus possible to carry simultaneously a test on one ring, and to build a new pavement on another ring. Each arm of the carrousel can be equipped with different wheel configurations ( single or dual wheels, mounted on simple, tandem or tridem axles). The maximum load on each arm is 130 kilo newton. The transverse wander of traffic can also be reproduced. The experimental pavements are built using normal roadwork equipment, and the materials are produced in plants of the Nantes area. The test track is generally divided in several test sections, (usually four), which are tested simultaneously. Pavements are generally instrumented using strain gages, temperature probes, and vertical displacement transducers. Other transducers, such as accelerometers, pressure cells, or moisture content sensors are also used. Different in situ tests, like deflection measurements, FWD tests, transversal and longitudinal profile measurements, are also performed. The figure presents an example of test on low traffic pavements, with unbound granular bases. The objective was to calibrate the designed method for flexible pavements. For this purpose, four different pavement structures, with increasing design lives were tested. Their behavior has also been compared with a "reference" pavement, with a bituminous base. The IFSTTAR accelerated testing facility is used for many different applications: Testing of innovative pavement materials and structures, Testing of pavement maintenance and reinforcement methods. validation and calibration of pavement design methods. Indeed, pavement design models needs to be adjusted using "calibration factors", determined by comparing predicted and observed pavement life durations. Testing of instrumentation and monitoring equipment. Reminder of the key points. Full scale accelerated pavement tests are used to accelerate traffic loading, and to test pavements up to failure, in a limited period of time. The iFSTTAR carrousel is designed to simulate closely in situ conditions: It can apply 1 million loads per month, with a maximum load of 130 kilometers, and a maximum loading speed of 100 kilometers per hour. The pavements are instrumented, to monitor their mechanical behavior. Full scale accelerated tests are used to test the resistance to traffic of new pavement materials and pavement structures, to validate pavement design methods. Thanks for your attention...