Fineness Modulus Of Sand

Fineness Modulus Of Sand | FM Calculation & Grading (Semi-Log)- Download PDF

Sand is a natural resource obtained from pits, rivers, seas, and deserts, which can play an important part in Engineering Construction. Sand is a granular material that consists of particles of finely divided rock i.e. pure silica (SiO2) Silicon dioxide. Using of sand in civil engineering such as filling under floors, basements, fine aggregate at concrete, mortar, and plaster, etc. But all types of sand are not suitable for such works. Determines sand properties such as Fineness Modulus, Specific Gravity, Bulking of Sand, Compressive strength, and Silt and clay content, which is best for mortar and concrete work or suitable for plastering and finishing work.

Classification of Sand

Sand is commonly acquired from rivers, seas, and deserts. It can be classified according to size and source.

Classified According to Size:

Mostly in construction Sand is being used as a fine aggregate. That is into different-sized for different types of work. These can be divided into three types. SourceDr.MA.Aziz (Engineering Materials: Page-118)

  • Fine Sand: This grain of sand is passed through Sieve No. 16 standard ASTM Sieve size.
  • Moderately Coarse Sand: All the sand particles should pass through Sieve No. 8 standard ASTM Sieve size.
  • Coarse Sand: All the particles should pass through Sive No. 4 standard ASTM Sieve size.

Grading Requirements for Fine Aggregate

SourceASTM This size is ASTM standard specification for concrete aggregate C33/C33M-18.

Sieve No.OpeningPercent Passing
3/8″9.5 mm100
No. 44.75 mm95 to 100
No. 82.36 mm80 to 100
No. 161.18 mm50 to 85
No. 30600 µm or 0.6 mm25 to 60
No. 50300 µm or 0.3 mm5 to 30
No. 100150 µm or 0.15 mm0 to 10
No. 20075 µm or 0.075 mm0 to 3

Classified According to Source:

There are four kinds of sand: Pit sand, river sand, sea sand, and desert sand.

  • Pit Sand: This sand is obtained from a Pit that contains clay and other impurities which should be screened and washed before construction uses. The sand shapes are sharp angular and porous mostly free from salt, which is suggested for mortar work and the color is light browned or yellowish.
  • River Sand: Basically most of the sand comes from rivers in construction work. River sand is obtained from the River-bed and it is fine round and polished which contains earthy impurities like pebbles and gravel etc. Should be screened and washed before construction. It is more well-graded than other sources. Generally, three types of sand are obtained from rivers fine, medium, and coarse. source The Times of India [But, the fear is that there is a shortage of sand for rapid construction that the river stock cannot replenish.] source ResearchGate [Therefore the engineers are searching for another alternative way like sea and desert sand.]
  • Sea Sand: This sand is also fine, round, and polished but it is not useable in general conditions because it might contain sea salts that corrosion steel and absorb moisture from the atmosphere causing reduced structure durability and permanent dampness. source ResearchGate [ However, due to the shortage of natural pit and river sand resources, people have been trying to use sea sand and desert sand instead in recent years. Fiber Reinforced Polymer (FRP) can be an extensive solution for the uses of different materials in construction as reducing corrosion of steel.]
  • Desert Sand: As a replacement for natural river sand, desert sand would be a great implementation in civil engineering in China and Meidle-East where there is the largest source of deserts. SourceResearchGate But the desert sand shape is fine and rounded which can weaken the structure.
analysis of desert sand grains
Fig: ESEM analysis of desert sand grains. SourceResearchGate

Source ScienceDirect [A recent research by Central South University in China has told us that desert sand and river sand composition of the same particles of SiO2 and Al2O3. But the particles of size are smaller than river sand. Due to the stable composition and use as finer aggregate in cement-based material (CBM) prove that the incorporation of Desert Sand greatly improves by filling effect of ultrafine particles of the porosity, durability, and mechanical properties. The CBM annually adopted around the world about 32 to 50 billion tons of natural river sand as a result of the over-exploitation of natural sources, which burdens environmental pollution and further threatens in civil living environment.]

Fineness Modulus Of Sand (FM): Calculation & Grading

The fineness modulus is abbreviated as FM. FM of sand (fine aggregate ASTM standard) is an index number that represents the average size of the grain of sand. It is calculated by performing a Sieve Analysis with ASTM standard sieves 3″, 1/2″, 3/4″, 3/8″, No. 4, No. 16, No. 30, No. 50, and No. 100 and dividing the sum of the cumulative percentages retained on each sieve by 100 gives the fineness modulus value or FM.

FM or Fineness Modulus Calculation

This sand was collected from the Shari Ghat River-Bed located in the Sylhet area in Bangladesh. Because of the vast amount of sand used from the Shari river bed in this region. SourceResearchGate (Sieve Analysis Data)

Sieve Analysis 01: Fine Aggregate

Sieve SizeStandard Opening (mm)Material retained (gm)Percent of material retained (%)Cumulative Percent Retained (%)Percent Finer/ PassFineness Modulus FM
No. 44.7500.00.0100.0
No. 82.3610.10.199.9
No. 161.18101.01.198.9
No. 300.60383.84.995.1
No. 500.3019119.124.076.0
No. 1000.1574374.398.31.7
No. 2000.075121.299.50.5
Total1000FM 1.28

FM= {(0+0.1+1.1+4.9+24.0+98.3)÷100}=1.28

This sand Fineness modulus is 1.28 which is a fine aggregate.

Gradation Curve of Sand in Semi-log

From percent fineer or pass and sieve size can draw particle size gradation curve of fine sand.

Gradation Curve of Fine Sand
Fig: Gradation Curve of Sand (Fine)

Sive Analysis 02: Medium Aggregate

Sieve SizeStandard Opening (mm)Material retained (gm)Percent of material retained (%)Cumulative Percent Retained (%)Percent Finer/ PassFineness Modulus FM
No. 44.75111.11.198.9
No. 82.36313.14.295.8
No. 161.1828428.432.667.4
No. 300.6035435.468.032.0
No. 500.3020520.588.511.5
No. 1000.1511111.199.60.4
No. 2000.07530.399.90.1
Total1000FM 2.94

FM= {(1.1+4.2+32.6+68+88.5+99.6)÷100}=2.94

Gradation Curve of Sand in Semi-log

From percent fineer or pass and sieve size can draw particle size gradation curve of medium sand.

Gradation Curve of Sand
Fig: Gradation Curve of Sand (Medium)


At present, we are getting sand from a few selected natural locations such as pits and river beds, but the scope should be increased by proper use of sea and desert sand. And assure the use of properties standard of ASTM for example fineness modulus, Bulking of Sand, Compressive strength, etc. which would provide more sustainability in the structure.

PDF Download of this Article
Download Now

Leave a Reply

Your email address will not be published. Required fields are marked *

Choose the right one

Trending posts in 24 hours

Popular Posts


Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors

Become a Writer

If you are interested in writing in "CivilEngineer9" blogs about Civil engineering,
engineering news & architectural project, drawings and softwares.
Create an account too easy.