[MUSIC] Hello, my name is Gilles Gauthier. I am responsible for the technical coordination and product development at Total Bitumen. You will now see a different grading system based on the measurement of viscosity called the Viscosity Grading system. Viscosity grade was developed in the early 1960s In this new grading system, a scientific viscosity test replaced the empirical penetration test as the key asphalt binder characterization. The viscosity grade bitumens are specified by methods describing ASTM and AASHTO standards. For instance, an AC20 binder is a bitumen which viscosity equals 2,000 poise at 60 degrees. Viscosity is measured in poise. The lower the number of poise, the lower the viscosity, and thus, the more easily a substance flows. This grading applied to original bitumen samples called AC grades, or aged residue samples called AR grades. The AR viscosity test is based on the viscosity of aged residue from the rolling thin film oven test. With AC grading, the asphalt binder is characterized by the properties it possess before it undergoes the asphalt mix manufacturing process. The AR grading system is an attempt to simulate asphalt binder properties after is undergoes the typical asphalt manufacturing process and thus it should be more representative on how asphalt binder behaves in asphalt pavements. Original viscosity grades range from AC 2.5 to AC 40. RTFO viscosity grades range from AR 1000 to AR 16,000. It is up to the purchaser to specify the applicable table of limits. Viscosity grading also quantifies the following asphalt binder characteristics. Viscosity at 60 degrees, viscosity at 135 degrees, needle penetration at 25 degrees, flashpoint temperature, ductility at 25 degrees, solubility in solvent, rolling thin oven test for short term aging, followed by viscosity at 60 degrees and ductility at 25 degrees. The viscosity grading system has certain advantages compared to the European system. Unlike penetration viscosity is a fundamental engineering parameter. It also provides information on the consistency of bitumen at three key temperatures. 25 degrees which is the approximate average ambient pavement temperature. 60 degrees which is the approximate maximal pavement surface temperature. And 135 degrees which is the approximate asphalt mixing temperature. These three measurements provide a feeling on the materials temperature susceptibility. Also, testing equipment and standards are widely available. But this system also adds its downsides, there is no assessment of the bitumen properties at low service temperature. When using the AC grading system, thin film oven test residues, viscosities can vary greatly within the same AC grade. And finally, the testing is more expensive and takes longer than the penetration test. The viscosity grading system has been very widely used from the 1960s to the 1990s, but has been replaced since then in most countries. For instance it has been replaced in the United States by the Superpave Performance Grading. It is still enforced in some countries including India, Australia, Latin America, and some countries in Africa like Ghana. As a conclusion let's now summarize what we have learned about the viscosity rating system for bitumen. It is based on the measurement of a fundamental property, which is viscosity at 60 degrees. It is applied on original and RTFO aged bitumen, and it is still used in many countries in the world. Thank you for your attention. [MUSIC]