Estimating Sheet

# How to calculate the quantity of cement, sand and aggregate for 1m3 of concrete

Construction Software With adherence to IS456:2000, there are various types of concrete grades like M5, M7.5, M10, M15 etc., here M is defined as Mix and the number behind M is defined as characteristic compressive strength(fck) of the concrete in N/mm2 @28 days when examined with 15cm×15cm×15cm cube in direct compression test.

Similar method will be applicable for finding out the different grades of concrete mixes. The Concrete mix ratio for M20 grade of concrete is 1:1.5:3 i.e. 1 part of cement, 1.5 part of sand (fine aggregate) and 3 parts of aggregate (crushed stone) in volume and then batched for mixing.

According to BS 8500-2 British/European standards, the grade of concrete is defined as C10, C15, C20,C25, etc., where ‘C’ stands for ‘Concrete Strength class’ and number following C stands for characteristic Compressive strength of Concrete in N/mm2 @ 28 days when tested with the 15cm dia & 30cm height cylinder in direct compression test. The grade of concrete is also termed as C16/20, C20/25, C25/30, etc.

1MPA = N/mm2
Several grades of concrete contains various concrete mix proportions or ratios.

How to work out the quantities of cement, sand and aggregate in 1m3 of concrete:-
Guess a nominal mix grade of concrete as M20. Similar process will be applicable to work out different grades of concrete.

Concrete Mix Design for M20 Grade Concrete:-
According to IS456:2000, M20 Grade concrete proportion is = 1 : 1.5 : 3
So, the total volume = 1 + 1.5 + 3 = 5.5
At the time of concreting when wet concrete is placed, it becomes solidified after specific standard time.
Volume of dry Concrete = 1.54 to 1.57 times Volume of wet concrete

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Here, 1.57 is taken as factor of safety
Therefore, total concrete volume required is 1.57 m3

Calculation of Volume of Cement in 1m3 of Concrete:-

The Quantity of Cement in Concrete will be measured with the following formula :-

Volume of Cement
= Cement⁄Cement+Sand+Aggregate x 1.57
= 1 / 1+1.5+3 x 1.57 = 0.28 m3

1m3 of cement = 1440 kgs
0.28m3 of cement = 1440 x 0.28 = 403.2 kgs
For 1m3 of Concrete = 403.2Kgs of Cement will be necessary.

No. of Cement Bags necessary for 1m3 of Concrete = 403/50 = 8.06 ~ 8 bags
Therefore, 8 bags of cement is necessary for 1m3 of concrete.

The above formula will be same for finding out the quantity of sand and aggregate for 1m3 of Concrete. But the ratio will be changed for sand and aggregates. 