3.5. Mortar
Mortar is a mixture of cementitious material and sand. It is used for the construction of masonry as well as plastering and rendering works. According the European standard [48], the mortar used for masonry must have a compressive strength of 7.5 N/mm2, equivalent to a cement–sand ratio of 1–5. This ratio represents energy consumption in the production of 1300 MJ/m3[47].