In order to calculate how many bags of cement required in 1m3, you should know about the dry density of cement.

In general Density = Mass/Volume

Dry Density of cement = Dry Mass/ Unit Volume

Got confused? Let me explain: In general cement consists of moisture content so Mass of cement includes Cement with Moisture content

Dry Mass includes cement without moisture content

So, Usually, 4% of moisture content is present in cement.

Dry Density of Cement                   = 1440kg/m3

Each bag of cement consists of     = 50kg

No. of bags in 1m3                           = 1440/50

= 29bags (approx)

Result:

Approximately 29 bags are required for 1m3 of cement.

Assuming

1- Grade of mortar = 1:6 (cement : sand)

2- Class A brick (19 cm x 9 cm x 9 cm)

3- Volume of brick work = 1.0 m^3, (wall size =1*1*1 =1.0 m^3)

4- Thickness of mortar = 10 mm

Step 1 :- Calculation of bricks

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^3

since thickness of mortar = 10 mm (0.01 m)

Volume of brick with mortar = (0.19+0.01) x (0.09+0.1) x (0.09+0.1) = 0.2×0.1×0.1 = 0.002 m^3

Number of brick required in brick work volume = 1.0 m^3

therefore,

No.of bricks = 1.0/ (0.002) = 500 Nos.

consider the percentage of waste as 10 % or 15 %

Total no. of bricks = 500 + (10 x 500 )/100=550

Step 2 :- Calculation for quantity of mortar

Since we need 500 no of bricks

volume occupied by bricks = No of bricks x volume of one brick

Volume of bricks = 500 x 0.001539 = 0.7695 m^3

Volume of mortar = Volume of brick work – Volume of Bricks

therefore,

volume of Mortar = 1.0 – 0.7695 = 0.2305 m^3

Step 3:- Calculation for Quantity of Cement

Cement = (dry volume of mortar x Cement ratio)/ sum of the ratio,s(proportion)

Dry volume of Mortar = 1.33 x 0.2305 = 0.3065 m^3 ( 33% increment due to volume shrink after water addition )

Vol. of cement= (0.3065 x 1) / (1+6) = 0.3065/7= 0.043795 m^3

cement (kg) = 0.043795 x 1440 = 63.0648 kg

No. of bags = 63.0648 / 50 = 1.26 bags approximately 2 bags

Step 4 :- Calculation for Quantity of Sand

Sand = (dry volume of mortar x Sand ratio)/ sum of the ratio,s(proportion)

Sand = 0.3065*6/7 = 0.2627 m^3

or

sand = cement volume x 6 ( since 1:6 grade of mortar)

Sand = 0.043795 * 6 =0.2627 m^3

sand = 0.2627 x 1920 = 504.384 kg /1000 = 0.5043 tonnes or

sand = 0.2627 x 35.3147 = 9.27 cft or

sand = 0.2627 x 0.354 = 0.0930 brass

So, For

1. Grade of mortar = 1:6 (cement : sand)
2. Class A brick (19 cm x 9 cm x 9 cm)
3. Volume of brickwork = 1.0 m^3
4. Thickness of mortar = 10 mm

Number of Bricks = 500

Cement = 1.26 bags of 50 Kg

Sand = 0.2627 m^3