This paper describes the research run on ceramic materials, and more specifically fired clay roof tiles, ground to a fineness suitable for use as an active replacement for portland cements (PCs). The utilization of waste products from calcined clay roof tiles as a pozzolanic material in the cement manufacture is studied. One of the first materials used as pozzolans in the history was thermal-treated clay, a material similar to the calcined clay precast elements. For this study, the materials selected are clay products that have been eliminated for different reasons: a wrong temperature inside the kiln, dimensional and mechanical failures, and durability loss. The results showed that these products have good pozzolanic properties; at an early age, the pozzolanic activity was found to be higher than fly ash, although it was lower than silica fume. The morphology of clay tile-PC pastes are similar to the morphology of the pastes containing other pozzolanic materials. Hydrated calcium aluminate products are generated when the preparation method yields less compact pastes with a greater voids' volume to accommodate these products. The hydrated calcium aluminate phases were analyzed using scanning electronic microscopy and X-ray diffraction techniques.