Before a pavement is placed the surface to be paved must be prepared. Pavements constructed without adequate surface preparation may not meet smoothness specifications, may not bond to the existing pavement (in the case of overlays) or may fail because of inadequate subgrade support.

HMA is produced in a plant that proportions, blends, and heats aggregate and asphalt to produce an HMA that conforming to JMF  requirements.  There are two basic types of HMA plants commonly in use today: the batch plant, and the drum mix plant.  Batch plants produce HMA in individual batches while drum plants produce HMA in a continuous operation.

Mix transport involves everything required to convey HMA from a production facility to a paving site including truck loading, weighing and ticketing, hauling to the paving site, dumping of the mix into the paver or material transfer vehicle hopper, and truck return to the HMA production facility (Roberts et al. 1996).  Ideally, the goal of mix transport should be to maintain mix characteristics between the production facility and the paving site.

Mix laydown involves everything used to place the delivered HMA on the desired surface at the desired thickness.  The asphalt paver is the principal machine involved in mix laydown and is assisted by the material transfer vehicle (MTV) or material transfer device (MTD) in some instances.

Quality has become one of the most important consumer decision factors in the selecting among competing products and services.  This is true not only for individual consumers but also for large corporations, government organizations and the taxpaying public as a group.  In its broadest sense, quality is a degree of excellence: the extent to which something is fit for its purpose.  In the narrow sense, product or service quality is defined as conformance with requirement, freedom from defects or contamination, or simply a degree of customer satisfaction.

Specifications are used (1) to convey information concerning desired products from a buyer to a seller or potential seller, (2) as a basis for competitive bidding for the delivery of products, and (3) to measure compliance to contracts.  Typically, four types of specifications; proprietary product, method, end-result and performance specifications; are generally recognized in the construction industry.

Segregation and temperature differentials are construction-related HMA pavement problems that can lead to early pavement failure.  Washington State has been a leader in researching, identifying and combating these problems.