Calculation of cement mortar is done to determine the quantity of cement and sand for different ratios of the cement mortar. For instance, for the cement mortar ration 1:6, total 5.50 bags of cement and 1.14 cum of sand will be required.
Calculation of Cement Mortar
Let us calculate the volume of mterial required for 1 cum of mortar
Vol of dry mortar = 33% extra of wet mortar = 1+0.33×1 = 1.33 cum (considering 33% volume of voids)
Calculation of Cement Mortar 1:6
Volume of cement in cum = (1×1.33) / 7 = 0.19m3 Volume of 1 bag of cement = (Weight /Density) = 50 / 1440 = 0.0347 m3 No. of cement bags needed = 0.19 / 0.0347 = 5.48 bags.
Volume of sand = (6x 1.33) /7 = 1.14 m3
Calculation of Cement Mortar 1:5
Volume of cement in cum = (1×1.33) / 6 = 0.22m3 No. of cement bags needed = 0.22/ 0.0347 = 6.34 bags.
Volume of sand = (5x 1.33) /6 = 1.11 m3
Calculation of Cement Mortar 1:4
Volume of cement in cum = (1×1.33) / 5 = 0.27m3 No. of cement bags needed = 0.27/ 0.0347 = 7.78 bags.
Volume of sand = (4x 1.33) /5 = 1.06 m3
Calculation of Cement Mortar 1:3
Volume of cement in cum = (1×1.33) / 4 = 0.33 m3 No. of cement bags needed = 0.33/ 0.0347 = 9.51 bags.
Volume of sand = (3x 1.33) /4 = 1.00 m3
Calculation of Cement Mortar 1:2
Volume of cement in cum = (1×1.33) / 3 = 0.44 m3 No. of cement bags needed = 0.44/ 0.0347 = 12.68 bags.
Volume of sand = (2x 1.33) /3 = 0.89 m3
Calculation of Cement Mortar 1:1
Volume of cement in cum = (1×1.33) / 2 = 0.67 m3 No. of cement bags needed = 0.67/ 0.0347 = 19.31 bags.
Volume of sand = (1x 1.33) /2 = 0.67 m3
| Cement Mortar Ratio | Sum | Volume of Cement | No. of bags of Cement | Volume of Sand |
| Cement Mortar 1:6 | 1+6 = 7 | =(1×1.33)/7= 0.19 cum | 0.19/0.0347 =5.48 | =(6×1.33)/7=1.14 cum |
| Cement Mortar 1:5 | 1+5 = 6 | =(1×1.33)/6= 0.22 cum | 0.22/0.0347 =6.34 | =(5x 1.33 )/6=1.11 cum |
| Cement Mortar 1:4 | 1+4 = 5 | =(1×1.33)/5= 0.27 cum | 0.27/0.0347 =7.78 | =(4x 1.33 )/5=1.06 cum |
| Cement Mortar 1:3 | 1+3 = 4 | =(1×1.33)/4= 0.33 cum | 0.33/0.0347 =9.51 | =(3x 1.33 )/4=1.00 cum |
| Cement Mortar 1:2 | 1+2 = 3 | =(1×1.33)/3= 0.44 cum | 0.44/0.0347 =12.68 | =(2x 1.33 )/3=0.89 cum |
| Cement Mortar 1:1 | 1+1 = 2 | =(1×1.33)/2= 0.67 cum | 0.67/0.0347 =19.31 | =(1x 1.33 )/2=0.67 cum |
| Cement Mortar Ratio | Number of Bags of Cement | The volume of Sand in Cum | The volume of Sand in Cubic foot |
| Cement Mortar 1:6 | 5.50 | 1.14 | 40 |
| Cement Mortar 1:5 | 6 | 1.11 | 39 |
| Cement Mortar 1:4 | 8 | 1.06 | 37 |
| Cement Mortar 1:3 | 10 | 1.00 | 35 |
| Cement Mortar 1:2 | 13 | 0.89 | 31 |
| Cement Mortar 1:1 | 19.50 | 0.67 | 24 |
Cement Mortar Calculation in Brick Masonry
Cement mortar calculation in brick masonry consists of determining the total quantity of mortar required per unit volume of brick Masonry. By knowing the quantity of mortar we can calculate the total quantity of cement and sand in the masonry.
Calculation of Cement Mortar in 10 cum of Brick Masonry
- Size of standard Brick (with mortar) = 20 x10x10 (in cm).
- Total Number of Brick required for 1 cum of brickwork = 1/(0.20×0.10×0.10) = 500 Nos.
- Number of Bricks for 10 cum of brick masonry = 5000.
- Volume of bricks without mortar = 5000x 0.19x 0.09x 0.09 = 7.7 cum.
- Volume of mortar = total volume of brickwork – vol of bricks= 10-7.7 = 2.3 cum
- add 10% wastage = 2.3 + 0.1×2.3 = 2.53 cum.
- add 25% extra for dry mortar weight = 2.53+0.25×2.53 = 3.16 cum.
This is because the volume of dry mortar is always more than the volume of wet mortar. If you take 1 cum of dry mortar and add water to it for making mortar. The final volume will always be lower than the 1 cum. To account for this, 25% is added.
Now we have calculated that for 10 cum of brickwork approximately 3.16 cum of dry mortar is required.
Cement Mortar 1:6 Calculation in Brick Masonry
Volume of cement in cum = (1×3.16) / 7 = 0.45 m3
Volume of sand = 3.16 – 0.45 = 2.71 m3 or (6x 3.16) /7 = 2.71 m3
Volume of 1 bag of cement = (Weight /Density) = 50 / 1440 = 0.0347 m3
No. of cement bags needed = 0.45 / 0.0347 = 12.97 bags.
Cement Mortar 1:5 Calculation in Brick Masonry
Volume of cement in cum = (1×3.16) / 6 = 0.53 m3
Volume of sand = 3.16 – 0.53 = 2.63 m3 or (5x 3.16) /6 = 2.63 m3
No. of cement bags needed = 0.53 / 0.0347 = 15.27 bags.
Cement Mortar 1:4 Calculation in Brick Masonry
Volume of cement in cum = (1×3.16) / 5 = 0.63 m3
Volume of sand = 3.16 – 0.63 = 2.53 m3 or (4x 3.16) /5 = 2.53 m3
No. of cement bags needed = 0.63 / 0.0347 = 18.16 bags.
Cement Mortar 1:3 Calculation in Brick Masonry
Volume of cement in cum = (1×3.16) / 4 = 0.79 m3
Volume of sand = 3.16 – 0.79 = 2.37 m3 or (3x 3.16) /4 = 2.37 m3
No. of cement bags needed = 0.79 / 0.0347 = 22.77 bags.
Cement Mortar 1:2 Calculation in Brick Masonry
Volume of cement in cum = (1×3.16) / 3 = 1.05 m3
Volume of sand = 3.16 – 1.05 = 2.11 m3 or (2x 3.16) /3 = 2.11 m3
No. of cement bags needed = 1.05 / 0.0347 = 30.26 bags.
Cement Mortar 1:1 Calculation in Brick Masonry
Volume of cement in cum = (1×3.16) /2 = 1.58 m3
Volume of sand = 3.16 – 1.58 = 1.58 m3 or (1x 3.16) /2 = 1.58 m3
No. of cement bags needed = 1.58 / 0.0347 = 45.53 bags.
Summary
| Cement Mortar Ratio | Sum | Volume of Cement | No. of bags of Cement | Volume of Sand |
| Cement Mortar 1:6 | 1+6 = 7 | =(1×3.16)/7= 0.45 cum | 0.45/0.0347 =12.97 | =(6×3.16)/7=2.71 cum |
| Cement Mortar 1:5 | 1+5 = 6 | =(1×3.16)/6= 0.53 cum | 0.53/0.0347 =15.27 | =(5×3.16)/6=2.63 cum |
| Cement Mortar 1:4 | 1+4 = 5 | =(1×3.16)/5= 0.63 cum | 0.63/0.0347 =18.16 | =(4×3.16)/5=2.53 cum |
| Cement Mortar 1:3 | 1+3 = 4 | =(1×3.16)/4= 0.79 cum | 0.79/0.0347 =22.77 | =(3×3.16)/4=2.37 cum |
| Cement Mortar 1:2 | 1+2 = 3 | =(1×3.16)/3= 1.05 cum | 1.05/0.0347 =30.26 | =(2×3.16)/3=2.11 cum |
| Cement Mortar 1:1 | 1+1 = 2 | =(1×3.16)/2= 1.58 cum | 1.58/0.0347 =1.30 =45.53 | =(1×3.16)/2=1.58 cum C |
| Cement Mortar Ratio | Number of Bags of Cement | Volume of Sand in Cum | Volume of Sand in Cubic foot |
| Cement Mortar 1:6 | 13 | 2.71 | 98 |
| Cement Mortar 1:5 | 15 | 2.63 | 93 |
| Cement Mortar 1:4 | 18 | 2.53 | 89 |
| Cement Mortar 1:3 | 23 | 2.37 | 84 |
| Cement Mortar 1:2 | 30 | 2.11 | 75 |
| Cement Mortar 1:1 | 46 | 1.58 | 56 |
In above examples we have calculated the quantities of cement and sand in Cement Mortar and in Cement Brickwork. You can change the void content which I have taken for the calculation e.g. 33% for cement mortar. A similar example has been done by taking 60% void content by Theconstructor.org.
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