Hello again, I'm Mike Southern. You might remember me from the video on safe handling of bitumen. This video is intended to provide some background to bitumen specifications and how they are developed. These general principles apply to all bitumen specifications. Specifications are required so that producers and users of bituminous binders can agree on the functional properties of the binder at the point of sale. The starting point for development of a specification is the identification of the characteristics required for performance. In construction applications, the bitumen confers certain characteristics important to the performance of the finished product. It is important that the role played by the binder in the end use is understood, so that a specification focuses on the relevant characteristics of the binder. For asphalt mixtures, the pertinent characteristics might include: mechanical properties and stability, durability and safety in use. After the important characteristics of the end product have been defined, bitumen properties that relate to these characteristics can be identified. For each property, a defined test method is then selected with specific test conditions which will then provide values or limits that make up the product specification. Additional properties are often included in a specification relating to specific characteristics that might not be directly relevant to performance, but provide important practical information relating to handling and application. For example, mixing temperatures or flash-point. In use, Bitumens are often exposed to a wide temperature range, covering the daily and seasonal variations. Most specifications include a property relating to low service temperatures, generally to address the tendency of a binder to cracking; a high service temperature property, to address the tendency to permanent deformation (or rutting), and an intermediate service temperature property, often used for mixture or pavement design. In summary, most bitumen specifications contain specified test methods that measure properties relating to important characteristics of bitumen for the performance in their intended use. The properties relate to the main failure modes, such as low temperature cracking, often measured on laboratory-aged material, high temperature deformation, often measured on virgin, or short-term aged material, and properties to assist with the mixture and pavement design, measured at intermediate temperature. Thank you for your attention.