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Gradation of Coarse Aggregate by Sieve Analysis

AIM OF THE EXPERIMENT: To determine the gradation of coarse aggregate by sieve analysis.



Sieve Shaker motor operated
Fig 1: Sieve Shaker motor operated

Coarse aggregate is the one retained on 4.75 mm IS Sieve. When the aggregate contains sizes differently in suitable proportions, it is called graded aggregate. The workability of concrete is also improved with well graded aggregate. Single size aggregates make the concrete harsh and does not work well with trowel and between the cables, strands or sheathing. The coarse aggregate may be of the following types –

The graded coarse aggregate is defined by its nominal size i.e., 40 mm, 20 mm, 16 mm, 12.5 mm, etc. For example, a graded aggregate of nominal size 12.5 mm means an aggregate most of which passes the 12.5 mm IS Sieve. Because the aggregates are formed due to natural disintegration of rocks or by the artificial crushing of rock or gravel, they derive their many of the properties from the parent rocks. These properties are chemical, mineral composition, petrographic description, hardness, strength, pore structure, colour, etc. Other properties which are not possessed by parent rock or gravel are shape, size, texture, absorption, etc. Furthermore, sub-classifications are there like in shape, round, angular varieties are there, in unit weight classification normal weight, lightweight is there and many more. All these properties may have a considerable effect on the quality in fresh and hardened states.

Within these limits, the nominal maximum size of coarse aggregate may be as large as possible for low to moderately high strength concrete. The bigger the size of aggregate, lesser is the surface area and hence less amount of water is required for wetting the surface and less matrix or paste is required that lubricates the surface so as to reduce internal friction. For a given quantity of water and paste, bigger size of aggregate will give higher workability.Coarse aggregates are used in various tests like slump test, vee bee test, etc. in order to ascertain the suitability of coarse aggregate in making better quality of concrete.



  1. The sample should be oven dried at temperature 1000C to 1100C before weighing and sieving.
  2. The dried sample of coarse aggregate is weighed.
  3. The weighed sample is placed on the uppermost sieve. The sieve is arranged according to sizes.
  4. The sieve with biggest opening is kept on top while the sieve with smallest opening is kept at bottom.
  5. Below the sieve of smallest opening, pan is kept in order to collect the remaining samples which does not conform to the sieve sizes above.
  6. A brush is used to clean the additional particles or impurities remaining on the sieve shaker.
  7. After making all the arrangement the sieve shaker is turned on and it is operated continuously for around 10 – 15 minutes in order to obtain correct results.
  8. After operating the shaker is turned off and the sieves are taken out for weighing the remaining samples on each of the respective sieves.
  9. Cumulative weight passing through each sieve sizes are calculated as a percentage of the total sample weighed.

The coarse aggregate both graded and single sized shall be supplied in nominal sizes as per specifications given as under:

Weight of sample taken = __________ kg.

Table 1

Sl No. IS Sieve No Weight retained in kg % weight retained Cumulative % weight retained % passing As per IS 383-1970 Remarks
1 40 mm            
2 20 mm            
3 10 mm            
4 4.75 mm            

The minimum weight for different nominal sizes of aggregates may be taken as below:

Table 2

Maximum size present in substantial proportions in mm Maximum suggested weight of sample to be taken for sieving in kg Minimum weight of sample to be taken for sieving as per IS 2386 (Part-1)-1963 in kg
40 15 15
20 4 2
16 3 2
12.5 2 1
10 1 0.5

The sample of aggregates does/does not conform to IS 383-1970.


• The hand gloves should be worn during the experiment so as to avoid any injury.
• Safety shoes and aprons at the time of test must be worn for protection.
• Cleaning and drying before the commencement of test is recommended.
• Careful sieving should be adopted.
• The electric balance should be checked before weighing.
• Sieves should be arranged in correct order.

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Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

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One comment on "Gradation of Coarse Aggregate by Sieve Analysis"

Thin Thin Ni says:

Thank you very much for your support. I have got many help.

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