Fired clay masonry units production incorporating two-phase olive mill waste (alperujo)

This work deals with the use of alperujo, the main residue from the two-phase olive oil extraction process, as a raw material in fired clay masonry units production. Different amounts (3, 6 and 12 wt%) of clay were substituted by alperujo, and the properties of the resulting ceramic units were compared to those of conventional products. Results show that a number of advantages can be obtained. At 12 wt% alperujo addition, masonry units present lower density (1710 kg m−3 compared to 1850 kg m−3 reference value) and higher thermal insulation effectiveness (18% reduction in the bulk of fired clay thermal conductivity). With respect to mechanical properties, the fired bending strength attained of approximately 14 N mm−2 is sufficiently high for this type of unit. In addition, the heating value obtained from the organic content of the added alperujo can cause a decrease in the heating requirements in the firing process.