The fiberglass reinforcing additives selection studies have been carried out and it has been found that basaltic fiberglass at firing temperatures 1000… 1050°C does not melt and provides for the formation of a homogeneous porous ceramic structure penetrated by filaments of fiber located on the surface of the sample, without affecting the internal porosity of the material. The strength of the porous ceramic based on the clay raw material and the porous additive in the form of high-calcium wastes formed during the water purification by calcification at the power stations, when introducing the reinforcing additive components, depends on the iron oxide content.