Structural lightweight concrete has an in-place density on the order of 1400 to 1900 kg/m3 compared to normal-weight concrete with a density in the in the range of 2000 to 2400 kg/m3. For structural applications, the concrete strength should be greater than 17 MPa. The concrete mixture is made with lightweight coarse aggregate. In some cases, a portion or the entire fine aggregate may be a lightweight product. Lightweight aggregates used in structural lightweight concrete are typically expanded shale, clay or slate materials that have been fired in a rotary kiln to develop a porous structure.