Clay and Shale
The main difference between clay and shale is that shale is a fine-grained clastic sedimentary rock, mainly composed of clay minerals including illite, kaolinite and smectite, whereas clay is a soft rock-based compound. To transform clay and shale into pozzolans, they undergo a high-temperature calcination process before being ground into a fine powder to use as a SCM. The particles in calcined clay and shale are slightly larger than Portland cement grains, which has little effect on bleeding and segregation.
Application and Uses
Clay and shales can be used to make brick, pottery, tile, and Portland cement.