2. SL NAME ID E-mail
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02 Md.Nurul islma 1601007174 md.nurul976@gamal.com
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3. Sand is a naturally
occurring granular material composed of finely
divided rock and mineral particles
the most common constituent of sand is silica (silicon dioxide, or SiO2),
usually in the form of quartz.
4. Sand is formed by the weathering of rocks. Based on the natural
sources from which sand is obtained, it is classified as follwos:
Pit sand
River sand
Sea sand
5. PIT SAND
This sand is obtained by
forming pits in soils.
It is excavated from a
depth of about 1-2 m from
the ground level.
This sand is found as
deposits in soil and it
consists of sharp angular
grains, which are free from
salts.
6. It serves as an excellent material for mortar or concrete work.
Pit sand must be made free from clay and other organic
materials before it can be used in mortal.
A coating of oxide of iron over the sand grains should be
removed.
PIT SAND
7. This sand is widely used for all purpose. It is obtained
from the banks or beds of rivers and it consists of fine
rounded grains. The presence of fine rounded grains is
due to mutual attrition under the action of water
current.
RIVER
SAND
8. The river sand is available in clean conditions.
The river sand is almost white in color.
RIVER
SAND
9. This is obtained from sea shores.
It is brown in color and it also has the fine
rounded grain.
SEA
SAND
10. As it is obtained from sea it contains salt, which is used in
attracting moisture from atmosphere.
Such absorption causes dampness and disintegration of
work.
It is generally not used for engineering purpose due to its
retards setting action of cement. It is normally used for non.
SEA
SAND
11. Based on the grain size distribution
Fine sand: The sand passing through a sieve with
clear opening of 1.5875 mm is known as fine sand.
Coarse Sand: The sand passing through a sieve with
clear opening of 3.175 mm is known as coarse sand.
Gravelly sand: The sand passing through a sieve with
clear opening of 7.62 mm is known as Gravelly sand.
It is generally used for concrete work
12. Grading of sand:
IS Sieve Percentage passing for
Grading Zone I Grading Zone II Grading Zone
III
Grading Zone
IV
10mm 100 100 100 100
4.75 mm 90-100 90-100 90-100 90-100
2.36 mm 60-95 75-100 85-100 95-100
1.18 mm 30-70 55-90 75-100 90-100
600 micron 15-34 35-59 60-79 80-100
300 micron 5-20 8-30 12-40 15-50
150 micron 0-10 0-10 0-10 0-15
13. • It should be clean and coarse.
• It should be free from any organic or vegetable
matter; usually 3-4 per cent clay is permitted.
• It should be chemically inert.
• It should contain sharp, angular, coarse and durable
the atmophere.
• It should be well graded,i.e., it should contain
particles of various sizes in suitable proportions.
• It should be strong and durable.
• It should be clean and free from coatings of clay and
silt.
PROPERTIES OF GOOD SAND
14. Sand for Construction Works
Different construction works require different standards of
sand for construction.
• Brick Works: Finest modulus of fine sand should be 1.2 to 1.5
and silt contents should not be more than 4%.
• Plastering Works: Finest modulus of fine sand should not be
more than 1.5 and silt contents should not be more than 4%.
• Concreting Works: Coarse sand should be used with finest
modulus 2.5 to 3.5 and silt contents should not be more than
4%.
15. Functions of sand in Mortar/Concrete:
• Offers requisite surface area for the film of
binding material to adhere and spread.
• Increases the volume of mortar & consequently
makes mortar more economical.
• A well-graded sand adds to the density of
mortars and concrete.
• Prevents excessive shrinkage of mortar.
• Since inert material, it renders structure more
resistant against atmospheric agencies.
16. Tests for sand:
If present in sand, it can be ascertained by
determining the percentage loss in weight of a
sample of sand after washing the same with clean
water and then sieving through #200 opening size.
However, field test can be performed by rubbing a
small amount of sand between finger tips. If clay
spots are left on finger tips, it indicates the
existence of clay in the considerable amount.
Test for silt and clay:
17. Test for silt:
Can be tested by putting some amount in mouth. The test will reflect the
presence of any salt
Test for Organic matter:
Make 3% solution of NaOH and put some sand into the solution.
Close the bottle for 24-hrs and meanwhile shake the solution
vigorously. The color of the liquid turns brown if any organic matter
is present in sand. The darkness of color gives the estimation of the
amount of organic matter exists in the salt
Substitute for sand:
• If good sand is not available in the nearby of the site, the
substitutes may be used.
• Stone screenings: Fine particles obtained by screening crushed
stones. The grains are sharp and strong, and hence impart
better strength to the concrete if used.
• Surkhi: Obtained from finely powdered burnt clay (brick). Also
obtained by grinding slightly under-burnt bricks. It disintegrates
under the action of air & humidity; not used for external mortar.
18. BULKING OF SAND
The increase in the volume of sand due to the presence of
moisture is known as bulking of sand. This is due to the fact that
moisture forms a film of water around the sand particles and this
results in an increase in the volume of sand. The extent of bulking
depends on the grading of sand. The finer the material the more
will be the increase in volume for the given moisture content.
For a moisture content of 5-8 per cent, the increase in volume may
be about 20-40 per cent depending upon the gradation of sand.
When the moisture content is further increased, the sand particles
pack near each other and the amount of bulking is decreased.
Hence, dry sand and the sand completely.
19.
20. Deleterious materials in sand
Sand shall not contain any harmful impurities such as iron, pyrites,
alkalis, salts, coal or other organic impurities, mica, shale or similar
laminated materials, soft fragments, sea shale in such quantities as
to affect adversely the hardening, strength of durability of the
mortar. The maximum quantities of clay, fine silt, fine dust and
organic impurities in the sand / marble dust shall not exceed the
following limits.
(a) Clay, fine silt and fine dust when determined in accordance
within nor more than 5% by mass in IS 2386, natural sand or
crushed gravel sand and crushed stone sand.
(b) Organic impurities when determined in color of the liquid shall
be lighter in lighter in accordance with IS 2386, Than that specified
in the code.
