MUSIC] Hello and bonjour. I am Jean-Pascal Planche. I am the Vice President for Asphalt and Petroleum Technologies at the Western Research Institute in Laramie, Wyoming in the USA. Have been involved in Bitumen asphalt research development and marketing for almost 30 years, both in Europe and in the US. This is a real pleasure for me to share with you some generalities of Bitumen characteristics and the impact on road construction. The purpose of this video session is to present the main properties of Bitumen for road construction. Where we go over adhesion, cohesion, viscoelasticity, and thermoplasticity in. We will see how these properties relate and impact the performance of the Bitumen pavement. We will make a general overview of the various types of damages that can impact the performance of a pavement. But if you're really riding, cracking, more thermal and fatigue, and raveling, there are many more but those like skid resistance and roughness I'll not directly link to the bitumen properties. We will focus on the bitumen properties that affect the performance, such as adhesion being Bitumen being a glue, mechanical properties, and some ageing considerations. The performance of a pavement usually deteriorates with time as a function of the traffic loading and the climatic conditions. Among the various damages occurring, some are more related to Bitumen properties than others. Those damages include rutting created by heavy loading trucks in the summer time, fatigue cracking also related to truck [INAUDIBLE] repetition but under cooler conditions like in the spring or in the fall. Thermal cracking, related to sudden drop in temperature during the cold winter, not necessarily in the presence of traffic. And raveling. This is the progressive loss of surface or edge aggregates and asphalt binder due to weathering and aging. Bitumen is the glue that maintains together the aggregates and makes the pavement skeleton. Adhesion is a complex property that depends on the couple Bitumen aggregate, but subjected to warm interference, as in a strange love story. Adhesion depends on the Bitumen chemistry, particulates polarity, on the aggregate chemical nature, and surface characteristics. All these parameters will define the strength of the adhesion bond between the Bitumen, the mineral fines that make the mast stick and the aggregates. Viscoelasticity is the tendency of a substance to behave like both viscous liquid and an elastic solid under external force. The temperatures expands by pavements vary greatly. The Bitumen can go from purely solid on cold winter days to nearly liquid on hot summer days. The viscoelastic nature of the Bitumen is crucial to its performance in the field. It should ideally retain some viscous behavior at low temperatures to prevent cracking, but still be elastic enough at hot temperatures to prevent running. Bitumens are often doped with poly modifiers to enhance the viscoelastic range and performance. Bitumen is also considered a thermoplastic material. That is, it will become soft when heated and hard again when cooled, without substantially altering its physical properties. This is a very important quality for Bitumen to have because it allows to flow and be pumped from place to place and to coat and adhere to aggregate while hot and still return to a firm, elastic state that allows traffic loads on the pavement after cooling. This pavement will then resist rutting, cracking and other dimensions. Viscoelasticity and thermoplasticity of Bitumens all play key roles in field performance. However, Bitumen will react with oxygen in the air due to its complex blend of organic molecules, changing its physical characteristics over time. Bitumen will eventually become stiffer, more plastic and brittle, and these changes are irreversible. Physical hardening in Bitumens can also occur as a result of spanning time at low temperatures, however, this type of hardening is reversible. Those aging phenomena are extremely complex. And will require a whole dedicated session. In conclusion, it is clear that Bitumen is quite an incredible material due its combination of properties. As an adhesive material it acts as a glue for the aggregates, and preserves the integrity and water resistance of the pavement. As a viscoelastic material it's able to withstand a wide range of temperatures without critical failure. And as a thermoplastic material, it is easily workable at high temperatures, yet durable enough to withstand traffic loads when cooled back down. Finally, its physical limitation can be compensated by the addition of polymer modifiers and other additives. And they will be presented in two forthcoming videos. Or by special types of blending. With that, I thank you for your attention, and I hope that you had fun watching. [MUSIC]