Following is a simple method used by engineers to calculate cement, sand and aggregate to produce different grade of concrete like M5, M7.5, M10, M15 and M20. if you don’t want to learn the math involved in the design, you can use the table given at the end of the article to produce different grade of concrete.
There are two ways to design the concrete mix. They are Design mix method and nominal mix method. Once you know the math behind the design you can easily design any grade of concrete for different purposes in different units.
DIFFERENCE BETWEEN NOMINAL MIX CONCRETE AND DESIGN MIX CONCRETE
In the design mix method, materials are proportioned based on the procedure and rules given in IS456(2000) and IS10262(2009) codebooks. In this method, cement, sand and aggregates are always batched in terms of weight, and concrete can be designed for different environmental conditions and different needs. Hence, if you prepare concrete using design mix method you can save cost and get good quality of concrete.
In nominal mix method, materials are proportioned based on prescribed approximation and experience to attain the different grade of concrete. Cement, sand and aggregates are usually batched in terms of volume using pans, batching boxes etc.., Nominal mix method is easier to follow in site and they are easier to design and measure hence they are often used in site to produce concrete up to M20 grade.
UNDERSTANDING CONCRETE GRADE AND CONCRETE MIX RATIOS
Concrete is classified into different grades like M5, M7.5, M10, M15 etc., where M stands for Mix and the following number stands for characteristic compressive strength(fck) of concrete in 28 days in the Direct Compression test. So, if you produce M20 grade concrete then you will get the compressive strength of 20 N/mm2 in 28 days after mixing and casting.
The strength of concrete is based on the ratio of cement, sand, aggregate used to prepare concrete. Hence it is important to determine the mix ratio through previous experience and Guidelines. Concrete mix ratios are usually in the form of cement : Sand: Aggregate. For example, if the concrete mix ratio of M20 concrete is 1:1.5:3 then 1 part of cement, 1.5 part of sand and 3 part of aggregate in volume should be taken to produce concrete.
Prescribed concrete Mix ratios for all grades of concrete are given below
GRADE | MIX RATIO |
---|---|
M 5 | 1 : 5 : 10 |
M 7.5 | 1 : 4 : 8 |
M 10 | 1 : 3 : 6 |
M 15 | 1 : 2 : 4 |
M 20 | 1 : 1.5 : 3 |
Above concrete mix ratios are not strictly practised in the site. You will often notice that the contractors increase the quantity of sand and reduce the quantity of cement to reduce the cost. Increasing the sand content will increase the workability of concrete which is good for mixing and placing but increasing the sand content will decrease the percentage of cement in concrete hence the strength and durability of the concrete will be affected. It is advisable not to increase the sand content more than 30 per cent than the above-prescribed ratio.
DESIGN OF NOMINAL MIX CONCRETE FOR ONE CUBIC METER OF M20 CONCRETE
Though you want to prepare 1 cubic meter of concrete, the total volume of cement sand and aggregate required will be more than 1 cu.m. Because, while mixing, cement and sand has to fill the gaps between the aggregate(crushed stone) before taking their own place. Hence if you want to produce concrete with 20 mm aggregate then the total volume of cement sand and aggregate you require will be 1.55 cubic meters, and if you want to produce concrete with 40 mm aggregate then the total volume of cement sand and aggregate you require will be 1.52 cubic meters.
Let’s calculate material required for M20 grade to prepare one cubic meter concrete.
Cement sand and aggregate ratio for M20 grade concrete is 1:1.5:3
- Cement = 1 Part
- Sand = 1.5 Part
- Aggregate = 3 Part
- Total Parts = 1 + 1.5 + 3 = 5.5
- Total Material Required per cubic meter of concrete= 1.55
Volume of 1 part | = (1 / 5.5) x 1.55 |
---|---|
= 0.282 cu.m | |
Volume of cement | = Ratio x1 part |
= 1 x 0.282 | |
= 0.282 cu.m | |
Volume of sand | = Ratio x 1 part |
= 1.5 x 0.282 | |
= 0.423 cu.m | |
Volume of aggregate | = Ratio x 1 part |
= 3 x 0.282 | |
= 0.846 cu.m |
Conversion of Units of the Material for site conditions
Cement is often bought in 50kg bags hence we must convert our calculated quantity to bags.
Weight of cement | = volume x density |
---|---|
= 0.282x 1440 | |
= 406kg |
No of cement bags required to prepare 1 cubic meter = 400 / 50 = 8 bags
Hence we require nearly 8 bags to prepare one cubic meter of M20 grade concrete.
Aggregates are often bought in Units through lorries and tippers. One cubic meter is 35.32 Cubic feet. One unit is equal to 100 cubic feet.
Sand in cft | = Volume x 35.32 |
---|---|
= 0.423 x 35.32 | |
= 15 cft | |
=0.15 unit |
Hence we require 15 cft of aggregate to prepare one cubic meter of M20 grade
Aggregate in cft | = Volume of sand x 2 |
---|---|
=15 cft x 2 | |
= 302 cft | |
= 0.30 unit |
Hence we require 30 cft of aggregate to prepare one cubic meter of M20 grade concrete.
M20 GRADE – MATERIAL CALCULATION USING GAUGE BOX AND PAN
Gauge boxes, pans are used for Volume batching in site. Volume of a gauge box is 0.35 cu.m(1cft) which is a volume of 1 bag of cement. For M20 grade, use 1 bag of cement, 1.5 boxes of sand and 3 boxes of aggregate. These are our results….
QUANTITY | CEMENT | SAND | AGG. |
---|---|---|---|
1cu.m | 0.28cu.m | 0.42cu.m | 0.85cu.m |
1cu.m | 400kg | 15 cft | 30cft |
1bag | 1 | 1.5cft | 3cft |
Likewise, cement, sand and aggregate for different concrete grades with 20mm aggregate (Total dry material = 1.55)….
GRADE | CEMENT | SAND | AGG. |
---|---|---|---|
M20 | 0.28cu.m | 0.42cu.m | 0.85cu.m |
400kg | 15cft | 30 cft | |
M15 | 0.22cu.m | 0.44cu.m | 0.89cu.m |
320kg | 15.5cft | 31cft | |
M10 | 0.16cu.m | 0.47cu.m | 0.93cu.m |
225kg | 16.5cft | 33cft |
GRADE | CEMENT | SAND | AGG. |
---|---|---|---|
M10 | 0.15cu.m | 0.46cu.m | 0.91cu.m |
220kg | 16.5 cft | 32 cft | |
M7.5 | 0.18cu.m | 0.47cu.m | 0.94cu.m |
170kg | 16.5cft | 33cft | |
M5 | 0.1cu.m | 0.475cu.m | 1 cu.m |
140kg | 17 cft | 33.5cft |
DESIGN OF NOMINAL MIX CONCRETE BY WEIGHT AS PER IS CODE
QUANTITY OF CEMENT SAND AND AGGREGATE IN WEIGHT PER BAG (50KG) OF CEMENT
IS456 Code book recommends the following quantities of total aggregate per 50kg of cement to produce nominal mix concrete.
GRADE | TOTAL ( FINE + COARSE ) |
---|---|
M 5 | 800 kg |
M 7.5 | 625 kg |
M 10 | 480 kg |
M 15 | 330 kg |
M 20 | 250 kg |
Let’s find out the quantity needed to produce M20 grade by the codal procedure. Sand is confirmed to Zone II – average grading. The ratio of fine to coarse aggregate is chosen as usual as 1:2. From the above table we know we need 250kg of total dry aggregate for our concrete.
sand per bag of cement | = (1 / (1+2)) x 250 kg |
---|---|
=83 kg ~ 85 kg | |
aggregate per bag of cement | = (2 / (1+2)) x 250 kg |
= 166 kg ~ 165 kg |
Likewise, the weight of cement, sand and aggregate per bag of cement for different concrete grades …
GRADE | CEMENT | SAND | AGGREGATE |
---|---|---|---|
M20 | 1bag | 85 kg | 165 kg |
M15 | 1bag | 110 kg | 220 kg |
M10 | 1bag | 160 kg | 320 kg |
M7.5 | 1bag | 210 kg | 415 kg |
M5 | 1bag | 265 kg | 535 kg |
WATER REQUIREMENT FOR NOMINAL MIX CONCRETE
Water is taken based on the weight of cement and the required workability. For design mix concrete codebook suggests to use suitable Water/Cement ratio based on different factors but for nominal mix concrete codebook suggests the following quantities per bag of cement.
GRADE | WATER PER 50KG OF CEMENT IN LITERS |
---|---|
M5 | 60 |
M7.5 | 45 |
M10 | 34 |
M15 | 32 |
M20 | 30 |
how can i calculate sand and aggregate per cum in kilogram
How can weight calaculate sand and aggregate per cum
Since many readers are asking the same question I have updated the post. Read the post again or click here
any more questions?
sir I’m kathavarayan BE civil Engineer Steels calucaled I need sie
I will publish about steel calculation soon. In the meantime You can refer “Estimation and quantity surveying” book by Dutta
I have updated the post. In the end of the post you will find what you are looking for.
volume of aggregate Ã— density of aggregate
Ah, Thanks for your input.
Is this method also applicable for designing nominal mixture of M15 grade
Yes of course but instead of multiply 1.5 in the volume required formula, you should multiply 1.55.
NIRANJAN DASH
multiply by 1.57 instead of 1.5
i want 1 : 3 : 6 how much sand qty
for what grade
1:3:6 is a M10 grade concrete. As per IS456, for 50kg bag of cement you will need 480 kg of total aggregate i.e., 160kg of sand and 320kg of coarse aggregate.
i think its 450kg for total aggregate , so 150kg sand and 300kg CA
Yes that’s what code book suggests If you are looking for weigh batching
M 35
The ratio is same for river sand and Robo sand( M-Sand).
Yes
how can we apply this for different dimensions(cross section)?¡.e in my case i do have 1.7m*1.7m*0.5 footing pad which is prepared to be filled.
Calculate the concrete quantity required in cubic meter and then multiply the quantity with the cement sand and aggregate for 1 cubic meter of concrete.
In your case
Volume of concrete = 1.7 x 1.7 x 0.5 = 1.4 cu.m
It looks like you are using m20 grade mix with extra sand. If you follow that mix proportion then to calculate use this following method.
Total ratio = 1 + 2 + 3 = 6
Cement required = (1/6) x 1.5 = 0.25 cu.m (refer the post to change cu.m to bags)
Sand = 0.25 x 2 = 0.5 cu.m
Aggregate = 0.25 x 3 = 0.75 cu.m
Sir int his case we did calculate sand and aggregate in cubic feet but how we cn use it at site in execution plz tell me quickly
You can calculate by counting head Pan. If you are using M15 grade concrete then for every 1 pan of cement use 2 pan of fine aggregate and 4 pan of coarse aggregate.
very nice imfo. in that site
how to calculate for M40 grade ?
You can design M40 Grade using code book
M40 Concrete should be designed as per code.
Md Saif
volume of raw material 1.5 is constant value or sand value
It’s a approximate constant empirical value.
thanks
how to calculate rod
5.5 mq concrete me sand cement &metal 1&2 no kitna jaayega
100 Sq.ft how to calculate brick
M 50 mix designe
Concrete above M20 Should be designed using “IS 10262: Guidelines for concrete mix design proportioning” Code book
l want make ready made wall sise of
1’w×5’L×1″T what is the proportion of cement sand aggregate and water
if need iron rod or (gale )then what is size
For What purpose?. Generally, walls are constructed with bricks and mortor. Cement and sand in the ratio of 1:5.
Good
Thank you
useful information
in design mix
a/c to is :10262-2009, how to calculate volume of coarse and fine aggregate for different water cement ratio.
How do we know that for M20 concrete we must have a ratio of 1:1.5:3
???
What is ratio M25 grade ?
There is no nominal mix ratio for m25 grade. some people will say that m25 grade is 1:1:2 but they are wrong. Codebook says that concrete above M20 grade should be designed only by procedure from the IS10262
What is the size of the box use for measuring aggregates for volume mixing
2 Head pan = 1.25 cuft = 1 bag of cement
1 batching box = 1.25 cuft = 1 bag of cement
What is weight of fine & coarse aggregate and weight of cement in kg for nominal cement concrete mix 1:1:2
1:1:2 is considered as a nominal mix ratio for m25 but its wrong. there is no nominal mix ratio for m25 mix. mix above m25 should be designed with code book.
Thank you for clear explanation.
how to calculate quantity of water required to make concrete ?
(explain it with any of concrete grades)
Its in the end of the post….
GRADE WATER PER 50KG OF CEMENT IN LITERS
M5………..60 liters
M7.5……..45
M10……..34
M15……..32
M20……..30
Sir how I calculate the 1:4:5 grade of concrete
I dont think that is a good ratio to obtain good quality of concrete, Mr. Hussain. You will end up using too much sand which is not good for concrete. Maybe 1:3:5 is a good ratio. Either way, you should follow the same procedure given above.
Good morning Sir, by the help of your concrete ratio. I can solve my BOQ. Thank you.
From
It’s my pleasure
Good morning sir, It is very useful information. Now I have started G+2 building construction in 2000SFT (Ground floor area). I have given the contract for construction. They are using 1 : 2.5 : 3 (Actually they have suggested 1 : 2.5 : 3.5 ) for concrete and 1 : 6 for brick work. We are using Ultratech 53 grade cement (OPC) cement. May I know is it good?
Contractors usually add extra sand to reduce the cement content and also to increase the workability(consistency) of concrete. The strength of the concrete greatly depends on the density of the concrete hence we should not play with the ratio of sand to aggregate. I would suggest the ratio of 1:2:3 or 1:1.5:3 for M20 grade concrete and 1:2:4 or 1:2.5:3.5 for M15 grade concrete.
If you prepare concrete with your ration then the concrete will have too much sand. Too much sand causes shrinkage and this will not give high-density concrete. Hence use 1:2:3 for good strength and 1:2.5:3.5 for moderate strength.
If you want to increase strength then reduce the water content and use Chemical admixtures like super plasticisers. If you want good compaction and high density then you can use two different types of aggregates like 10mm aggregate and 20mm aggregate.
Your contributions have been very helpful. Thank, you.
Hello, and happy new year!
Thank you very much Aminu. Happy new year to you too..
For 1m3 ,how much weight of concrete will come
Density of the concrete is around 2400kg/m3. The weight of the concrete is around 2400kg/m3. Usually, weight of the norma concrete will be less than 2400kg/m3
What’s density of sand and aggregate?
Bulk density of both sand and aggregate is usually between 1500kg/m3 to 1700kg/m3