History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c29.s2.t4.2

v1.c29.s2.t4.2

At Harappa, gypsum cement of light grey colour was used in certain buildings. It consists of variable mixture of sand (20 to 40%), gypsum (45 to 75%) and lime (2 to 25%). Lime mortar with sizeable percentage of magnesium is also used in Indus Civilization. It contains calcium carbonate (26 to 57%), magnesium carbonate (4 to 11%) and sand clay (34 to 61%). The high percentage of sand and clay in lime plaster suggests that it was prepared by burning *Kankar* (calcarious nodules). The use of lime was restricted to drains and floors. *(See Table 1)*.