Buildex, Inc. is a Midwestern US producer of expanded shale lightweight aggregate marketed as Buildex lightweight aggregate. The word Haydite in our header refers to our roots that go back to Stephen J. Hayde, the inventor of expanded shale lightweight aggregate produced by the rotary kiln process. Buildex is a construction material used primarily in the production of lightweight concrete masonry (Haydite block and Buildex SmartWall Systems concrete masonry units), lightweight structural concrete, and also as a lightweight fill aggregate. There are many other significant uses, as well.