**M30 Grade of Concrete Mix Design Calculation Procedure**is all about achieving

*target strength*,

*water cement ratio*and perfect

*proportions of Cement, Sand and Aggregate*to produce a good

*concrete*to achieve its

*target strength*. Here we described the full

*procedure of M30 concrete mix design calculation*,

*proportion*and

*formula*with

*ratio for M30 grade as per MoRTH and IS Codes*

Click here for** Concrete Mix Design of M40 and M60.**

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

#### REQUIRED DATA FOR M30 GRADE OF CONCRETE MIX DESIGN

#### REQUIRED TEST DATA FOR MATERIALS FOR M30 GRADE OF CONCRETE MIX DESIGN

**Specific Gravity detais :**

Material | Specific gravity |

Cement | 3.15 |

Coarse Aggregate 20mm | 2.885 |

Coarse Aggregate 12.5mm | 2.857 |

Fine Aggregate | 2.723 |

**Water Absorption details**:

Material | Water Absorption |

Coarse Aggregate 20 mm | 0.42% |

Coarse Aggregate 12.5 mm | 0.47% |

Fine Aggregate | 1.38% |

### Calculation for Target Mean Strength

### Selection of Water Cement Ratio for M30 Grade of Concrete Mix design

#### SELECTION OF WATER FOR M30 GRADE OF CONCRETE MIX DESIGN

**CEMENT CONTENT**

#### PROPORTION OF VOLUME OF COARSE AND FINE AGGREGATE CONTENT FOR M30 GRADE OF CONCRETE MIX DESIGN

## M30 Grade of Concrete Mix Design Calculation Formula

### Convert Volume into Weight for Concrete Mix

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

### Concrete Mix Design Ratio for M30

## Trial Mix – 1, ( for M30 Grade Concrete Mix Design)

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

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.

- Water cement ratio
- Proportion of cement, coarse aggregate, fine aggregate, water and admixture ( if required ).
- Workability ( slump ).
- Density
- Compressive strength

### Concrete Cube Required for Trial Mix

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

Age of Cube in days | Nos of cube required |

3 | 3 |

7 | 3 |

28 | 6 |

Total numbers of cubes – 12

You can increase the cube numbers for 3 days, 7 days or 28 days as per your requirement.

### Concrete Quantity Required for Trial Mix

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

so concrete quantity for 1 cube = 0.003375 cum.

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

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

so assumed concrete quantity = 0.045 cum.

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

#### Calculate the Material Weight for Trial

## Trial Mix Procedure ( Important )

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

#### Requirement of Workability

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

You have to check slump after each 30 minute interval up to 120 minutes ( 2 hour ).

### Trial Mix Cube Casting Procedure

- Cube casting shall be done just after 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 cast usually.
- Cubes shall be casted 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 accurate result.
- Maintain the temperature of lab or room where trial cubes are going to be casted 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 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-mould the trial cubes and give the identification by permanent marker. Do not use the nail to write on cubes.
- Place these trial cubes in water tank immediately, where water temperature shall be maintain at room temperature 27 +/- 2 degree centigrade.

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

As we described before, we casted 12 numbers of 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 water tank.
- Bring these cubes to compressive testing machine and let it dry. We should test cubes at least in surface saturated dry condition.
- Before test the cubes set the rate of loading of compression testing machine at 5 KN per second.
- Place the cube carefully in compression testing machine in center position.
- Start the compression testing machine and go to 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 condition then, there is chance to get little bit more strength.

In wet condition or SSD condition, concrete cube’s pores are full of water and when you compress these cubes in compressive testing machine, water inside the cube works like hydrolic pressure from inside and this pressure helps to crack the cube earlier than dry cubes.

### Required Compressive Strength for Trial Cubes

As we described before that our target mean 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

**Workability Result**

Initial | Collapse |

After 30 minute | 190 mm |

After 60 minute | 170 mm |

After 90 minute | 155 mm |

After 120 minute | 140 mm |

2.** Compressive Strength Result **

Sr.no. | Casting Date | Cube ID | Age of cube | Testing Date | Weight (gm) | Load (KN) | Strength (N/mm^{2) } | Avg Strength |

1 | 1- 03 -19 | Trial Mix-01 | 3 days | 4-03-19 | 8642 | 401.6 | 17.85 | 18.24 |

2 | 8603 | 397.4 | 17.66 | |||||

3 | 8586 | 432.0 | 19.20 | |||||

4 | 07 days | 8-03-19 | 8598 | 781.7 | 34.74 | 34.92 | ||

5 | 8655 | 812.3 | 36.10 | |||||

6 | 8670 | 763.2 | 33.92 | |||||

7 | 28 days | 29-03-19 | 8621 | 912.8 | 40.57 | 41.52 | ||

8 | 8639 | 953.0 | 42.36 | |||||

9 | 8572 | 936.9 | 41.64 | |||||

10 | 8640 | 929.4 | 41.31 | 41.43 | ||||

11 | 8612 | 946.5 | 42.07 | |||||

12 | 8648 | 920.6 | 40.92 |

So as you can see result above, we got 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/mm^{2} .

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 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 trial on 0.38.

Definitely compressive strength will increase while decreasing water cement ratio.

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

**CEMENT CONTENT FOR M30 GRADE OF CONCRETE MIX DESIGN**

**Proportion of Coarse and fine aggregate will be same**

#### Calculation for Materials Volume

#### Convert Volume into Weight for Concrete Mix

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

**Start the Trial Again with these detail described above**

#### Trial Mix Procedure for M30 Grade of Concrete Mix Design

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

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

#### Requirement of Workability

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

We have to check slump after each 30 minute interval up to 120 minutes ( 2 hour ).

#### 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 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 cast usually.
- Cubes shall be casted 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 accurate result.
- Maintain the temperature of lab or room where trial cubes are going to be casted 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 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-mould the trial cubes and give the identification by permanent marker. Do not use the nail to write on cubes.
- Place these trial cubes in water tank immediately, where water temperature shall be maintain at room temperature 27 +/- 2 degree centigrade.

#### Compressive Strength of Trial Cubes

As we described before, we casted 12 numbers of 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 water tank.
- Bring these cubes to compressive testing machine and let it dry. We should test cubes at least in surface saturated dry condition.
- Before test the cubes set the rate of loading of compression testing machine at 5 KN per second.
- Place the cube carefully in compression testing machine in center position.
- Start the compression testing machine and go to ultimate load.
- Note down the ultimate load reading.
- Same like 3 days, we should test for 7 days and 28 days.

#### Required Compressive Strength for Trial Cubes

As we described before that our target mean 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

**Workability Result**

Initial | Collapse |

After 30 minute | 180 mm |

After 60 minute | 165 mm |

After 90 minute | 150 mm |

After 120 minute | 135 mm |

2.** Compressive Strength Result **

Sr.no. | Casting Date | Cube ID | Age of cube | Testing Date | Weight (gm) | Load (KN) | Strength (N/mm^{2) } | Avg Strength |

1 | 1- 04 -19 | Trial Mix-02 | 3 days | 4-04-19 | 8671 | 412.0 | 18.31 | 18.44 |

2 | 8622 | 430.4 | 19.13 | |||||

3 | 8639 | 402.5 | 17.89 | |||||

4 | 07 days | 8-04-19 | 8706 | 800.6 | 35.58 | 35.83 | ||

5 | 8665 | 784.1 | 34.85 | |||||

6 | 8614 | 833.7 | 37.05 | |||||

7 | 28 days | 29-04-19 | 8698 | 961.3 | 42.72 | 42.47 | ||

8 | 8627 | 947.4 | 42.11 | |||||

9 | 8720 | 958.1 | 42.58 | |||||

10 | 8679 | 970.4 | 43.13 | 42.50 | ||||

11 | 8711 | 951.3 | 42.28 | |||||

12 | 8632 | 946.9 | 42.08 |

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

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 M30 grade of concrete.

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Click here for Compressive Strength of Concrete at 7 days, 28 days Calculation & Formula