This is a continuation of the previous article I posted How to do a compaction test or In-situ density test, about how to calculate a compaction test report. Here we are going to compute the bulk density of sand down to the degree of compaction of soil.
I would really want to pursue this article just to completely show the full process of getting the results of the test from taking the samples into calculations. So every site engineer, project engineer, consultant, inspector, as well as engineering student should know how it is done. This would be a guide and help them learn the procedures.
Here are the steps on how to calculate a compaction test or In-situ density test report.
You may watch the video here.
1. Compute the Bulk Density of Sand (the starting point ton how to calculate a compaction test)
The calculation of bulk density of sand shall be made in the laboratory before moving on to the site. Here are the values tabulated below.
| Values taken from the laboratory | ||
|---|---|---|
| V | 0.00785 m³ | Volume of calibrating container |
| M1 | 17,050 gm | Mass of the sand before pouring in the container |
| M2 | 3,425 gm | Mean value of mass of the sand in cone |
| M3 | 2,192 gm | Mean value of mass of the sand retained in the pouring cylinder |
Then calculate the Ms, mass of sand to fill the container. From the formula in the article linked above.
Ms = 17, 050 – 3, 420 – 2, 192
Therefore, Ms = 11, 438 gm.
Bulk density of sand, ρs = 11, 438 gm/ 0.00785 m³
Therefore, ρs = 1, 457. 07 Kgm/m³.
2. Calculate the Bulk Density of Soil
After getting all the values from the actual compaction test done on site. Let us go directly to the calculations because what we are really concerned about here is “how to get the degree of compaction?” and how it is computed? So if you have with you right now the test report from the third-party laboratory, you might try to use the solutions we’ve done here in order for you to know how the test report is computed.
Below is the parameter for the calculation of bulk density of soil which was obtained from the actual compaction test on site. From Item 5 on “How to do a compaction test or In-situ density test” the excavated soil from the hole shall place into a clean container or plastic container. It will be weighted as mass of the soil excavated (Me).
| Values taken on site | ||
|---|---|---|
| Me | 10, 345 gm | Mass of the soil excavated |
| M1 | 17, 050 gm | Mass of sand before pouring into the hole |
| M2 | 3, 425 gm | Mass of sand in cone (mean value) |
| M4 | 5, 155 gm | Mass of sand after pouring into the hole (mean value) |
Mf = 17, 050 – 3, 425 – 5, 155
Therefore, Mf = 8, 470 gm
Bulk density of soil, ρso = (10, 345 gm /8, 470 gm) x 1. 45 mg/m³ = 1.78 Mg/m³
3. Calculation of Moisture Content.
Below is the laboratory test of the same sample taken from the site.
Wc = 177.5 gm. – Mass of container in gm.
W1 = 1,045.7 gm. – Mass container and moist specimen in gm.
W2 = 975.6 gm. – Mass of container and oven-dried specimen in gm.
Mass of the water
Ww = W1 – W2 = 1, 045.7 – 975.6 = 70.1 gm.
Mass of the Solid particle
Ws = W2 – Wc = 975.6 – 177.5 = 798.1 gm.
MC = (Ww/Ws) x 100 = (70.1/798.1) x 100
Therefore, MC = 8.78 %
4. Calculate the Dry Density of Soil
After getting the result of moisture content you can now calculate the ρd from the formula written in “How to do a compaction test or In-situ density test.”
ρd = (100 x 1.78)/(100 + 8.78)
Therefore, ρd = 1. 64 Mg/m³
5. Calculate the Degree of Compaction
The degree of compaction is the basis and or the final acceptance once it is passed. The specification commonly says “The degree of compaction shall be not less than 95 percent of maximum dry density (MDD).”
Please note that you have to take first a sample soil where you are going to do a compaction test and test it for “Proctor test“ where you will get the maximum dry density or MDD that will use in the calculation of the Degree of Compaction.
The MDD, for instance, to be used in this calculation is 1.7 Mg/m³, but MDD may vary depending on the type of your soil. Below is the calculation of the degree of compaction.
DOC = (1.64/ 1.7) x 100
Therefore,
Degree of compaction, DOC = 96.5 %
The compaction test is passed and satisfactory because 96.5 percent is higher than the limit of 95 percent. The succeeding activity can now proceed.
Did you follow the above computation on how to calculate a compaction test report? If you do, please write your comment below.
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What is Bulk Density?
As the ratio of mass of soil to the total volume of water.
What the moisture content?
It is moisture content of the soil sample at which maximum dry unit weight is obtained.
What maximum dry density or MDD?
The dry density obtained by the compaction of soil at its optimum moisture contetn.
Hello since we can’t do compaction test on rocks the alternative testing is called water replacement method/testing can help me understand the concept behind it
Bless you man, thank you.
Hi Ali,
Welcome. God bless you too. Thanks for stopping by.
Regards,
Noel
How to calculate 95% proctor density test from formula. Is any formula for it.?
Proctor test is a separate test to find the maximum dry density of soil. From that test we get here 1.7 kg/m3
Hi Noel,
How do you calculate the kpa on a site that’s been built up in 150mm uniformed layers ? I have a compaction test report showing dry density of 88% and 2.06 t/m3
Dear sir, can we take MDD of soil as 1.7mg/m3 for all type of soil.
How to calculate the compaction ratio if I am given the following:
Moisture content = 7.6%
Dry density = 1.59Mg/m3
What is the minimum distance of soil sample getting in a building?
As long as you gonna get samples within the building area and well compacted, it would be fine. And make sure you comply with the frequency of the number of samples.
how we find volume decrease of soil when compaction.
Good day sir!
Can I ask what are the commonly used soil testing before building construction?
And kindly rate them sir. (from expensive to cheapest)
PS. for thesis details sir.
Thank you in advance for answering sir.
Hai
There are many
1. Plate load test test- very expensive
2. Compaction test- Usually sand replacement test- very cheaper compare to 1
Sir, good day!
Can I ask what are the commonly used soil testings before building construction?
And what are the cheapest of them? (kindly rank them sir from cheapest to expensive)
Thank you so much for answering sir.
In building construction, we commonly test the in-situ soil. The same soil will use for backfilling.
How to achieve 100% compaction values even my stockpile is passing all the test even I am rolling again and again?
Granular fill or engineered fill mostly achieves that.
Dear Sir… is it possible earth, sand & crusher run can achieve more than 100% degree of compaction?
Dear sir,what should be the maximum dry density of back filling soil?
It depends on the type of backfilling? If you will use in-situ it would be 95 percent.
Mass of the Solid particle
W2 = 520.2 gm. – Mass of container and oven dried specimen in gm.
Ww = W1 – W2 = 1, 045.7 – 650.2 = 395.5 gm.
Why did you take w2 650.2 instead of 520gm?
Can you please elaborate?..
Apologize for the mistakes. I have updated the calculations and now is corrected.
MC = (Ww/Ws) x 100 = (395.5/472.7) x 100
Therefore, MC = 8.4 %
but answer is 84% how it come 8.4%
please explain
For base course of crusher run material testing is done, how much time after the rolling complete?
Thanks for the information, please correct those numerical and units mistakes it will confuse others.
Is there any regulation on how many tests need to be performed due to area size? Or a calculation to determine how many tests should be done on a given area due to size?
Yes, and that is written in your specification.Example 3 tests in every 500 square meter. Make sure that you always check your spec.
Is there any relationship between omc and moisture content found on conducting test?
Very nice Mr. Noel.
Mass of the Solid particle
W2 = 520.2 gm. – Mass of container and oven dried specimen in gm.
Ww = W1 – W2 = 1, 045.7 – 650.2 = 395.5 gm.
Why did you take w2 650.2 instead of 520gm?
Can you please elaborate?..
I apologize for the mistakes. Now the calculations are updated.
It’s a very useful information, your page helped a lot in understanding the work procedure for QA/QC .
Thank you for sharing your experience with other. You’re doing a great job sir .
Thank you
Hasan Jarir
Is it possible to have a computed value of more than 100% using the above procedures.
what could be responsible for this and what is the engineering significance.
How to find the compaction is satisfactory?
Just read the article and you will find the answer.
Is there any IS Code to clarify the satisfactory compaction?
Can a buyer request a compaction report for a new house that was purchased? The builder had drenched the site the wrong way (garage on the left when it should be on the right) and now they have to fill, compact and start over. Do you think this would have any impact on the foundation later in time?
Can you elaborate further what type of drenching they have done?
Drenching or saturation in normal way will not affect to the existing foundation unless there was massive excavation or earth movement due to ground penetration like pile driving that could shaken the ground which the foundations are resting nearby.
For the compaction request, that is another part of their agreement, they can stipulate that into their contract. Because , as a buyer you have to ensure quality before getting the product or the property.
Very well said and informative.Thank you.
You’re welcome.