[交通运输]Superpave综述.ppt

* This test applies a static load to a simply supported beam of asphalt cement. Temperature is held constant using a liquid bath. A computer provides both equipment control and data acquisition. * Regardless of the type of equipment used, a sample of binder is molded into a “dog bone” shape with a uniform center cross section. The sample is pulled until the it breaks in the middle. The stress and strain at failure are recorded. This test requires a minimum strain before the sample fails. * This figure summarizes the testing required for the PG binder specification. * One of the primary purposes of the Superpave binder testing is to use that data for the development of a purchase specification for asphalt binders. * The binder designation is based on expected extremes of hot and cold pavement temperatures. * This is the binder specification - it is defined by AASHTO MP -1. * The approach to the PG system represents a change in philosophy. The specification requirement does not change; the temperature which the value has to meet changes with grade. * Many states have divided their territory into different regions. How many regions depends on the variation of climates. * This provides a brief summary of the steps needed to determine if an asphalt meets a particular PG specification. * This block will present background information on the traditional Marshall and Hveem mix design methods. At the conclusion of this block the student will have a general understanding of: The principal procedures and concepts used in Marshall and Hveem mix design techniques This material is covered in detail in Chapter 4 “Hot Mix Asphalt Mixture Design Methodology” of the recommended textbook. * The objective of HMA mix design is to develop an economical blend of aggregates and asphalt. In the developing of this blend the designer needs to consider both the first cost and the life cycle cost of the project. Considering only the first cost may result in a higher life