The approximate proportion of dry cement mortar required for brick work with bricks of nominal size 19 cm × 9 cm × 9 cm, with 15% extra for frog filling and wastage is: (assume 1 m of wet mortar = 1.25 m of dry mortar)
No. of bricks = (volume of brick work / volume of one brick with mortar) Volume of one brick (without mortar) = .19×.09×.09 = 0.001539 m since thickness of mortar = 10 mm (0.01 m) Volume of brick with mortar = (0.19 + 0.01) × (0.09 + 0.1) × (0.09 + 0.1) = 0.2 × 0.1 × 0.1 = 0.002 m Therefore, Number of bricks = = 500consider the percentage of waste as 15 % Total no. of bricks Now, Calculation for quantity of mortar Since we need 500 no of bricks Volume occupied by bricks = No of bricks × volume of one brick Volume of bricks = 500 × 0.001539 = 0.7695 m Volume of mortar = Volume of BRICK WORK – Volume of BRICKS therefore, Volume of Mortar = 1.0 – 0.7695 = 0.2305 m The approximate proportion of dry volume of cement mortar required for brick work = 1.33 × 0.2305 = 0.3065 m (Approx 33% increment due to volume shrink after water)