M30 Grade of Concrete Mix Design, Procedure with OPC 53 Cement

M30 grade concrete is a widely used high-strength concrete mix known for its 30 MPa compressive strength, making it essential for constructing high-rise buildings, bridges, and other key infrastructure. This concrete grade offers a balance of strength and workability, making it suitable for various applications where durability is critical.

M30 concrete is critical in the construction industry due to its ability to support heavy loads while maintaining structural integrity. The M30 concrete mix ratio is carefully calculated to achieve the desired strength and durability. It typically requires a precise balance of cement, sand, and aggregates to ensure optimal performance.

The strength of M30 grade concrete is ideal for constructing tall structures and ensuring durability in environments exposed to heavy loads and environmental stress. Understanding the correct M30 concrete mix ratio is essential for achieving the desired performance in construction projects, whether it’s for slabs, beams, columns, or other structural elements.

Discussion on Material Selection for M30 Concrete

The selection of materials for M30 grade concrete is crucial to achieving the desired compressive strength and durability. The choice of cement, aggregates, and water directly influences the performance of the concrete, so careful consideration must be given to quality, availability, and cost-effectiveness.

1. Cement Selection

• Quality: The cement used for M30 concrete should be of high quality, typically OPC 53 grade, as it provides the necessary strength. The fineness and consistency of the cement are critical to ensuring a strong bond with the aggregates.
• Availability: Ensure that the cement is readily available in the required quantity. Consistency in supply is important to maintain the uniformity of the M30 concrete mix ratio.
• Economic Considerations: While high-quality cement is necessary, it should also be cost-effective. The number of M30 cement bags required for the mix should be optimized to balance quality and cost.

2. Aggregate Selection

• Coarse Aggregates: The coarse aggregates should be clean, durable, and of a suitable size, typically 20mm for M30 grade concrete. The aggregates must be free from impurities such as clay or organic matter, which can weaken the concrete.
• Fine Aggregates: Fine aggregates (sand) should be well-graded and free from silt and clay. The m30 concrete ratio cement, sand, and aggregate should be carefully proportioned to ensure the mix achieves the required strength and workability.
• Availability and Economic Considerations: The aggregates should be locally sourced if possible, to reduce costs and ensure a steady supply. The m30 concrete mix ratio calculator can be used to determine the precise amounts needed, optimizing material usage.

3. Water Selection

• Quality: The water used in M30 concrete must be clean and free from harmful substances. Contaminants like acids, oils, and salts can adversely affect the strength and durability of the concrete.
• Quantity: The water-cement ratio is a critical factor in the m30 mix design. For M30 grade concrete, the water-cement ratio is usually kept at around 0.4 to 0.45. This ensures that the concrete is workable without compromising strength.
• Economic Considerations: While the cost of water is generally low, it is important to manage its usage carefully. Excess water can lead to a lower m30 grade concrete ratio, reducing the overall quality of the concrete.

Also, Read: Difference Between M25 and M30 Concrete

M30 Concrete Ratio

The M30 concrete mix ratio is a proportion of ingredients used to achieve a particular strength in concrete. The ratio is 1:0.75:1.5, which means for every 1 part cement, you need 0.75 parts sand and 1.5 parts aggregates when making 1 cubic meter of concrete

Concrete Mix Design IS Code

For Concrete mix design, we use, IS 456, and IS 10262.

Also, Read: Top 10 Tiles Companies in India

M30 Grade of Concrete Mix Design Calculation Formula

We are describing formula of concrete mix design calculation for M30 Grade of Concrete Mix Design but you can use this formula for any grade of concrete

The formula of Volume of material content = material weight / ( material specific gravity * total volume )

Volume of concrete = 1 Cu.M.

1 Cum = 1000 ltr ( in volume)

Volume calculation for materials:

• Cement Content = 350 / 3.15 x 1000 = 0.111 Cu.M.
• Water Content = 140 / 1.00 x 1000 = 0.140 Cu.M.
• Admixture = 1.80 / 1.17 x 1000 = 0.0015 Cu.M.
• Aggregate = 1- ( cement volume + water volume + admixture volume ) = 1 – ( 0.114 + 0.140 + 0.0015 ) = 0.745 Cu.M.

Now we got a volume of each material for use in concrete. Now convert material volume into weight.

Convert Volume into Weight for Concrete Mix

This formula can be used for any grade of concrete mix design.

Formula = Material weight = material volume x percentage of total volume x material sp. gravity x total volume.

• Mass of coarse aggregates 20 mm = 0.745 x 0.60 x 0.50 x 2.885 x 1000 = 644.8 Kg. =Say 645 Kg.
• Mass of coarse aggregates 12.5 mm = 0.745 x 0.60 x 0.50 x 2.857 x 1000 = 638.5 kg =Say 639 Kg.
• Mass of fine aggregates = 0.745 x 0.40 x 1.00 x 2.723 x 1000 = 811.5 Kg = Say: 812 Kg

Mix Proportion per CUM. for M30 Grade of Concrete Mix Design

• Cement: 350 Kg
• Water: 140 Kg
• 20 mm: 645 Kg
• 12.5 mm: 639 Kg
• Sand: 812 Kg

Dosage of admixture, by the Weight of Cement

0.45% of cement weight: 1.80 Kg

Note:

In moisture correction, Weights of Aggregate and water can be replaced by the weights of the free moisture on Aggregates.

Concrete Mix Design Ratio for M30

M30 mix ratio – 1 : 2.5 : 3.5

Trial Mix:1, (For M30 Grade Concrete Mix Design)

The trail mix is required to define the workability ( slump ), density, compaction, and, most of all, the compressive strength of different concrete grades for various purposes.

We are describing here trial for M30 Grade of Concrete Mix Design, but you can use this trial procedure for any grade of concrete.

In this trial mix, we design the following.

1. Water cement ratio
2. Proportion of cement, coarse aggregate, fine aggregate, water, and admixture ( if required ).
3. Workability ( slump ).
4. Density
5. Compressive strength

Concrete Cube Required for Trial Mix

To check the compressive strength of trial mix concrete, we have to cast at least 12 nos. of cubes.

Total Number of Cubes – 12

You can increase the cube numbers for three3 days,  7 days, or 28 days as per your requirement.

Concrete Quantity Required for Trial Mix

Volume of 1 cube mould = 0.150 x 0.150 x 0.150 = 0.003375 cum.

so concrete quantity for 1 cube = 0.003375 cum.

concrete quantity for 12 cubes = 0.003375 x 12 = 0.0405 cum.

We should take a little more quantity of concrete because it will stick on a trial mix drum and slump test purposes.

so assumed concrete quantity = 0.045 cum.

We should not take more quantity for the concrete trail mix because it doesn’t mix properly.

Calculate the Material Weight for Trial

As we calculated materials weight before for one cum.

• Cement: 360 Kg
• Water: 140 Kg
• 20 mm: 645 Kg
• 12.5 mm: 639 Kg
• Sand: 812 Kg
• Admixture: 1.80 Kg

Now we calculate the quantity of materials for a trail mix.

• Cement = 360 x 0.045 = 16.2 kg.
• Water = 140 x 0.045 = 6.3 kg.
• 20 mm = 645 x 0.045 = 29.03 kg.
• 12.5 mm = 639 x 0.045 = 28.76 kg.
• Sand = 812 x 0.045 = 36.54 kg.
• Admixture = 1.8 x 0.045 = 0.081 kg

Trial Mix Procedure

• Take the weights of all material as described above.
• After weighing materials, put coarse aggregates 20 mm and 12.5 mm first in the trial mix drum.
• Now add fine aggregate ( sand ) in trial mix drum and then add the cement.
• Mix these materials in the dry condition in a drum for at least 30 seconds.
• Then add 80 to 90 % of the water in a drum in many parts by adding throughout the mix.
• Add a bit more water in the mix, where you are going to add admixture.
• Mix the remaining water with the admixture, then add admixture in a concrete mix where you added a bit more water.
• It’s because, if the mix is fully coated with water, then it will not absorb admixture in it’s pores, and now admixture will perform his best performance.
• Finish these steps within two minutes.
• Check if any dry mix sticked inside the surface of a drum, instantly remove it manually from a surface by using the trowel. Stop the drum mixture for a maximum of 10 seconds for this action and restart it again.
• Mix it for continuously 5 minutes.
• Check the workability.
• This is called an initial slump. Note down.
• Don’t mix the concrete mix continuously; otherwise, the mix will produce more heat, and it causes a decrease in the slump of concrete mix.
• Start the mixer at the 5-minute interval for about 1 minute.

Requirement of Workability

As we described, our requirement of a slump is 125 – 150 mm at the site.

You have to check a slump after each 30-minute interval of up to 120 minutes ( 2 hours).

Trial Mix Cube Casting Procedure

• Cube casting shall be done just after a slump test after 2 hours.
• Cast the concrete cubes manually for better accuracy, don’t use the plate vibrator.
• Cast the concrete cubes by the same procedure as we usually cast.
• Cubes shall be cast in three-layer, and each layer’s thickness is 50 mm nearly.
• But strokes for each layer shall be between 35 to 45 no more difference for an accurate result.
• Maintain the temperature of the lab or room where trial cubes are going to be cast at 27 +/- 2-degree centigrade.
• After casting 12 numbers of trial cubes, place the casted cubes on a plane and firm platform. It should be a vibration-free place.
• Place cover sheet on top of each casted cubes to prevent water evaporation.
• Leave it for 24 hours.
• After 24 hours, de-mold the trial cubes and give the identification by a permanent marker. Do not use the nail to write on cubes.
• Place these trial cubes in the water tank immediately, where water temperature shall be maintained at room temperature 27 +/- 2-degree centigrade.

Compressive Strength of Trial Cubes for M30 Grade of Concrete Mix Design

As we described before, we cast 12 numbers of a cube for compressive strength

• 3 cubes for 3 days
• 3 cubes for 7 days
• and 6 cubes for 28 days.

So after 3 days of casting cubes, take out three cubes from the water tank. Bring these cubes to a compressive testing machine and let it dry. We should test cubes, at least in surface saturated dry conditions.

Before the test, the cubes set the rate of loading of the compression testing machine at 5 KN per second. Place the cube carefully in the compression testing machine in the center position.

Start the compression testing machine and go to the ultimate load. Note down the ultimate load reading. Same like 3 days, we should test for 7 days and 28 days.

Why Wet Cubes Get lower Strength than Dry Cubes

If cubes are dry more than SSD conditions then, there is a chance to get a little bit more strength.

Surface Saturated Dry (SSD) conditions mean that the aggregate is fully saturated with water but with no free water on the surface. In this state, the concrete cubes may show lower compressive strength because the water within the pores can create internal pressure during testing.

Required Compressive Strength for Trial Cubes

As we described before that our target means strength for M30 is 42 Mpa.

But for 3 days and 7 days, we are giving below

• Minimum compressive strength required in 3 days – 40 % – 17 Mpa
• Minimum compressive strength required in 7 days –  80 % – 34 Mpa

Trial Mix Result

1.Workability Result

2.Compressive Strength Result 

So as you can see from the result above, we got a good result in 3 days and 7 days, but we didn’t get in 28 days. Average of 28 days strength is ( 41.52 + 41.43 ) / 2 = 41.48 N/mm² .

Which is less than 42 MPa. As we described, as per MORTH 5th revision, our requirement in 28 days for M30 is 42 MPa.

So now we are going to decrease the water-cement ratio a bit.

Trial Mix: 2 ( for M30 Grade of Concrete Mix Design)

Previously we selected 0.39 water-cement ratio. Now we will do a trial on 0.38.

Definitely, compressive strength will increase while decreasing the water-cement ratio.

So we have to calculate our concrete mix design again on 0.38 water-cement ratio because if you change the water-cement ratio, then materials quantity will change too.

We are describing calculation in short here because we described before. If you are getting any doubt, please scroll above for full details.

Cement Content for M30 Grade of Concrete Mix Design

Water Cement Ratio: 0.38

Hence Cement content : 140.0 / 0.38 = 368.42 Kg

Say: 368 Kg

Hence Cement Content: 368 Kg

The proportion of Coarse and fine aggregate will be the same

Hence Coarse aggregate content for MSA 20 mm: 60%

• Sand content can be adopted, Max. : 40%
• Course Aggregate Proportions ( 20 mm : 10 mm ) : 50%

Calculation for Materials Volume

• Volume of concrete = 1 Cu.M.
• 1 Cum = 1000 ltr ( in volume)
• Volume calculation for materials:
• Cement Content = 368 / 3.15 X 1000 = 0.117 Cu.M.
• Water Content = 140 / 1.00 X 1000 = 0.140 Cu.M.
• Admixture = 1.80 / 1.17 X 1000 = 0.0015 Cu.M.
• Aggregate = 1- ( cement volume + water volume + admixture volume ) = 1 – ( 0.117 + 0.140 + 0.0015 ) = 0.742 Cu.M.

Now we got a volume of each material for use in concrete.

Now convert material volume into weight.

Convert Volume into Weight for Concrete Mix

• Mass of coarse aggregates 20 mm = 0.742 X 0.60 X 0.50 X 2.885 X 1000 = 642.2 Kg, Say 642 Kg.
• Mass of coarse aggregates 12.5 mm = 0.742 X 0.60 X 0.50 X 2.857 X 1000 = 636 kg, Say 636 Kg.
• Mass of fine aggregates = 0.742 X 0.40 X 1.00 X 2.723 X 1000 = 808.2 Kg, Say: 808 Kg

Mix Proportion per CUM. of M30 Grade of Concrete Mix Design

• Cement: 368 Kg
• Water: 140 Kg
• 20 mm: 642 Kg
• 12.5 mm: 636 Kg
• Sand: 808 Kg

Dosage of admixture, by the weight of Cement

0.45% of cement weight: 1.80 Kg

Start the Trial Again with these detail described above

Now we calculate the quantity of the material for a trail mix

• Cement = 368 * 0.045 = 16.56 kg
• Water = 140 * 0.045 = 6.3 kg
• 20 mm = 642 * 0.045 = 28.89 kg
• 12.5 mm = 636 * 0.045 = 28.62 kg
• Sand = 808 * 0.045 = 36.36 kg
• Admixture = 1.8 * 0.045 = 0.081 kg

Trial Mix Procedure

We are repeating the procedure because it’s very important tips for a trail mix.

• Take the weights of all material, as described above.
• After weighing materials, put coarse aggregates 20 mm and 12.5 mm first in the trial mix drum.
• Now add fine aggregate ( sand ) in trial mix drum and then add the cement.
• Mix these materials in the dry condition in a drum for at least 30 seconds.
• Then add 80 to 90 % of the water in a drum in many parts by adding throughout the mix.
• Add a bit more water in the mix, where you are going to add admixture.
• Mix the remaining water with the admixture, then add admixture in a concrete mix where you added a bit more water.
• It’s because, if the mix is fully coated with water, then it will not absorb admixture in it’s pores, and now admixture will perform his best performance.
• Finish these steps within two minutes.
• Check if any dry mix sticked inside the surface of a drum, instantly remove it manually from a surface by using a trowel. Stop the drum mixture for a maximum of 10 seconds for this action and restart it again.
• Mix it for continuously 5 minutes.
• Check the workability.
• This is called an initial slump. Note down.
• Don’t mix the concrete mix continuously; otherwise, the mix will produce more heat, and it causes a decrease in the slump of concrete mix.
• Start the mixer at the 5-minute interval for about 1 minute.

Requirement of Workability

As we described, our requirement of a slump is 125 – 150 mm at the site.

We have to check the slump after each 30-minute interval of up to 120 minutes ( 2 hours).

Trial Mix Cube Casting Procedure

We are repeating this because it’s very important tips for trial cube casting.

• Cube casting shall be done just after a slump test after 2 hours.
• Cast the concrete cubes manually for better accuracy, don’t use the plate vibrator.
• Cast the concrete cubes by the same procedure as we usually cast.
• Cubes shall be cast in three-layer, and each layer’s thickness is 50 mm nearly.
• But strokes for each layer shall be between 35 to 45. No more difference for an accurate result.
• Maintain the temperature of the lab or room where trial cubes are going to be cast at 27 +/- 2-degree centigrade.
• After casting 12 numbers of trial cubes, place the casted cubes on a plane and firm platform. It should be a vibration-free place.
• Place cover sheet on top of each casted cubes to prevent water evaporation.
• Leave it for 24 hours
• After 24 hours, de-mold the trial cubes and give the identification by a permanent marker. Do not use the nail to write on cubes.
• Place these trial cubes in the water tank immediately, where water temperature shall be maintained at room temperature 27 +/- 2-degree centigrade.

Required Compressive Strength for Trial Cubes

As we described before that our target means strength for M30 is 42 Mpa.

But for 3 days and 7 days, we are giving below

• Minimum compressive strength required in 3 days – 40 % – 17 Mpa
• Minimum compressive strength required in 7 days –  80 % – 34 Mpa

Trial Mix Result

1. Workability Result

2. Compressive Strength Result 

So as you can see from this result described above, we got a good result in 3 days, 7 days and 28 days. Average of 28 days strength is ( 42.47 + 42.5 ) / 2 = 42.49 N/mm² .

Which is greater than 42 MPa. As we described, as per MORTH 5th revision, our requirement in 28 days for M30 is 42 MPa.

So now, we got the perfect proportion for the M30 grade of concrete.

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