Similar appearance of mortar and brick masses in Algiers Casbah houses during the Ottoman period (16th- early 18th centuries)

Abstract

The mixture of traditional mortars used in the houses of the Algiers Casbah during the Ottoman period (16th-early 18th centuries) has a similar appearance to the bricks mass. Grains of fired crushed ceramics of 5 mm or more, pebbles from sedimentary stones, shale, remains of nummulite limestone from the Algerian Atlas, and ashes from the lime calcination can be found in the mixture. The mortar joints were applied to the mixed masonry walls in layers that were thicker than or equally thick to the rows of bricks, whereas in the floors they are layered in thick beds interspersed with bricks until reaching 30-40 cm. Unhydrated lime lumps are encountered due to the artisanal mixing with limited water amounts to maintain a compact mortar. The Reddish colour of these earth-based mortars stems from the use of quartz, sand with illite, hematite and other components detected by XRD, EDXRF and DTA tests carried out on material samples. In light of this study, it is concluded that the Roman tradition of using lime and fired crushed ceramics is maintained in the earth-based mortars of the Ottoman period; knowing that their appearance is similar to the bricks one can argue that the bricks look like a baked mortar.