Portland Pozzolana Cement (PPC) is made by mixing coal ash (Pozzolana) with the cement clinker. This cement is usually made by mixing 70% by weight of clinker, 25% Pozzolana, and 5% gypsum. Because of the relatively lower concentration of clinker, this cement is relatively slow setting. This does not necessarily mean this is poor quality cement. PPC cement is widely used in construction for plaster casting. PPC cements can also be used in construction of load bearing structures if the design of the structure is made to use PPC cement for structure building.