shows the water absorption of the bricks. Water absorption is related to the volume of the open pores (i.e., the pores that are connected with the specimen surface). In addition, water absorption is closely related to densification and the microstructures of the cementitious matrix. It can be observed that the reference bricks BW2, BW4 and BW5 showed higher water absorption values than the reference bricks (BW0 sample). This is related mainly to the presence of a high amount of clay minerals (kaolinite and illite/mica) and an organic matter in the waterworks waste sample that tends to influence the cement hydration reactions