AbstractThe effect of grog addition on the technological properties of a kaolinitic plastic clay used for bricks and roofing tiles production, from Campos dos Goytacazes, southeast of Brazil, has been studied. Grog from red bricks, produced at temperatures < 600ºC, was added to the clay up to 20 wt%. Extruded bodies were fired in an industrial furnace at 970ºC, a temperature normally used for roofing tiles. Green body samples were tested for mixing water, linear shrinkage and dry bulk density. Fired samples were tested for linear shrinkage, water absorption and flexural rupture strength. The microstructure of fired samples was evaluated by pore-size distribution, X-ray diffraction and scanning electron microscopy. The results showed that grog addition reduces the total linear shrinkage but does not effectively alter water absorption and flexural strength. These results indicate the possibility of use fired brick waste on roofing tile production.