Concrete is generally considered a cemented-aggregate mixture. In other words, aggregates are central to concrete and are bounded together by a cementitious matrix. Aggregates comprise a significant volume in most concrete mixtures. This is generally desirable because aggregates are less expensive than components of the paste, they provide the load-carrying capacity of a concrete mixture, and they provide dimensional stability. However, some failure mechanisms in pavement concretes can be attributed to issues related to the quality of the aggregate. The purpose of this course is to provide pavement engineers with information to help them specify and choose materials that will last for the desired lifetime of the pavement. The course material is based on FHWA Tech Brief: Materials-Related Distress: Aggregates.

At the conclusion of this course, the learner will have a better understanding of Aggregate Materials and Related Distress as well as the following:

•Aggregates and their properties

•The influence of Alkali-Silica Reactivity on cracking

•Various models and testing conditions for potential reactivity

•D-Cracking and various causes of it