The structures may be exposed to fire or high temperature conditionally or accidentally. Alteration in the behaviour of concrete structure is prospective under the exposure of elevated temperature. There is an urge to find the materials which can resist the alteration in physiochemical and strength properties of cementitious materials under higher temperature. In the present study, efficacy of elevated temperature on cement mortar consisting of admixtures and stone waste i.e. stone slurry powder was investigated and compared with specimens at room temperature. The aim of study was to examine the practicability of these materials under the exposure to high temperatures. The mortar specimens were exposed to various temperature i.e. 1500C, 3000C, 4500C and 6000C for duration of one hour and compared with unheated specimens. The change in mass and strength of mortar specimens at elevated temperature was studied. The mass of mortar specimens reduced as exposure temperature of specimens raised. The residual strength of mortar increased up to a certain temperature afterward it decreased. Stone slurry powder and calcium nitrate individually and in combination, can be used to resist thermal changes in the construction industries