Significant environmental advantages will be realized if industrial byproducts, such as fly ash, can be substituted in structural grade concrete. In the early 1990s, researchers at Montana State University/Western Transportation Institute (MSU/WTI) began investigating the feasibility of using industrial byproducts to produce concrete building materials. While the magnitude and nature of the projects at MSU/WTI have changed over the years, a common factor has been the use of fly ash as the sole binder in the concrete mixtures. This article details projects that have been constructed with this "fly ash concrete."