The document discusses various tests that are conducted on sand to determine its suitability for use in concrete. The key tests described are: moisture content, clay content, grain size distribution, permeability, strength, refractoriness, hardness, silt content, and bulking. These tests are important because sand properties like cleanliness, grain shape and size distribution influence the strength and durability of hardened concrete. Impurities in sand like silt or organic matter can weaken the final concrete.

2. BY: Salman Hafeez
Roll Number: 2KX5-CE-106
TO:
PROF. ADNAN SHAH

3. Relation of sand to concrete
Sand for concrete can be classified as soft or
sharp sand. Soft sand has a smooth surface on
the individual granules. It is natural sand formed
by erosion factors such as water movement on a
beach. Sharp sand granules have a rough
surface. This sand is the result of manufacturing
by crushing larger forms of aggregate.
The most important factor concerning sand used
in concrete is that it must be clean sand.
Impurities in the sand such as silt or organic
matter will weaken the final hardened concrete

4. 1. Moisture content test
2. Clay content test
3. Grain fitness test
4. Permeability test
5. Strength test
6. Refractoriness test
7. Mould hardness test
8. Organic impurities test
9. Silt content test
10. Particle size distribution
11. Bulking of sand
TYPES OF TESTS:

5. Moisture content test
• Moisture is the property of the moulding sand it is defined as the
amount of water present in the moulding sand. Low moisture
content in the moulding sand does not develop strength properties.
High moisture content decreases permeability.
• Procedures are:
• 1. 20 to 50 g of prepared sand is placed in the pan and is heated by
an infrared heater bulb for 2 to 3 minutes.
• 2. The moisture in the moulding sand is thus evaporated.
• 3. Moulding sand is taken out of the pan and reweighed.
• 4. The percentage of moisture can be calculated from the difference
in the weights, of the original moist and the consequently dried sand
samples.
• Percentage of moisture content = (W1-W2)/(W1) %
• Where, W1-Weight of the sand before drying,
• W2-Weight of the sand after drying.

6. Moisture content test

7. Clay content test
• Clay influences strength, permeability and other moulding
properties. It is responsible for bonding sand particles together.
• Procedures are:
• 1. Small quantity of prepared moulding sand was dried
• 2. Separate 50 g of dry moulding sand and transfer wash bottle.
• 3. Add 475cc of distilled water + 25cc of a 3% NaOH.
• 4. Agitate this mixture about 10 minutes with the help of sand
stirrer.
• 5. Fill the wash bottle with water up to the marker.
• 6. After the sand etc., has settled for about 10 minutes, Siphon
out the water from the wash bottle.
• 7. Dry the settled down sand.

8. Clay content test
• 8. The clay content can be determined from the
difference in weights of the initial and final sand
samples.
• Percentage of clay content = (W1-W2)/(W1) * 100
• Where, W1-Weight of the sand before drying,
• W2-Weight of the sand after drying.

9. Grain fitness test/ Sieving
• The grain size, distribution, grain fitness are determined with
the help of the fitness testing of moulding sands. The
apparatus consists of a number of standard sieves mounted
one above the other, on a power driven shaker.
• The shaker vibrates the sieves and the sand placed on the top
sieve gets screened and collects on different sieves depending
upon the various sizes of grains present in the moulding sand.
• The top sieve is coarsest and the bottom-most sieve is the
finest of all the sieves. In between sieve are placed in order of
fineness from top to bottom.

10. Grain fitness test/ Sieving
• Procedures are:
• 1. Sample of dry sand (clay removed sand) placed in
the upper sieve
• 2. Sand is vibrated for definite period
• 3. The amount of same retained on each sieve is
weighted.
• 4. Percentage distribution of grain is computed

11. Permeability test
• The quantity of air that will pass through a standard specimen of
the sand at a particular pressure condition is called the
permeability of the sand.
• Following are the major parts of the permeability test equipment:
• 1. An inverted bell jar, which floats in a water.
• 2. Specimen tube, for the purpose of hold the equipment
• 3. A manometer (measure the air pressure)
• Steps involved are:
• 1. The air (2000cc volume) held in the bell jar is forced to pass
through the sand specimen.
• 2. At this time air entering the specimen equal to the air escaped
through the specimen
• 3. Take the pressure reading in the manometer.
• 4. Note the time required for 2000cc of air to pass the sand
• 5. Calculate the permeability number

12. Permeability test
• 6. Permeability number (N) = ((V x
H) / (A x P x T))
• Where,
• V-Volume of air (cc)
• H-Height of the specimen (mm)
• A-Area of the specimen (mm2)
• P-Air pressure (gm / cm2)
• T-Time taken by the air to pass
through the sand (seconds)

13. Strength test
• Measurements of strength of moulding sands can be carried out
on the universal sand strength testing machine. The strength can
be measured in compression, shear and tension.
• The sands that could be tested are green sand, dry sand or core
sand. The compression and shear test involve the standard
cylindrical specimen that was used for the permeability test.
• A. Green compression strength:
• Green compression strength or simply green strength generally
refers to the stress required to rupture the sand specimen under
compressive loading. The sand specimen is taken out of the
specimen tube and is immediately (any delay causes the drying of
the sample which increases the strength) put on the strength
testing machine and the force required to cause the compression
failure is determined. The green strength of sands is generally in
the range of 30 to 160 KPa.

14. Strength test
B. Green shear strength:
• With a sand sample similar to the above test, a different
adapter is fitted in the universal machine so that the loading
now be made for the shearing of the sand sample.
• The stress required to shear the specimen along the axis is
then represented as the green shear strength. It may vary
from 10 to 50 KPa.
C. Dry strength:
• This test uses the standard specimens dried between 105 and
1100 C for 2 hours. Since the strength increases with drying, it
may be necessary to apply larger stresses than the previous
tests. The range of dry compression strengths found in
moulding sands is from 140 to 1800 KPa, depending on the
sand sample.

15. Strength test
Steps involved are:
1. Specimen is held between the grips
2. Apply the hydraulic pressure by rotating the hand wheel
3. Taking the deformation use of the indicators.

16. Refractoriness test
• The refractoriness is used to
measure the ability of the sand to
withstand the higher
temperature.
• Steps involved are:
• 1. Prepare a cylindrical specimen
of sand
• 2. Heating the specimen at 1500 C
for 2 hours
• 3. Observe the changes in
dimension and appearance
• 4. If the sand is good, it retains
specimen share and shows very
little expansion. If the sand is
poor, specimen will shrink and

17. Mould hardness test
• Hardness of the mould surface can be
tested with the help of an “indentation
hardness tester”. It consists of indicator,
spring loaded spherical indenter.
• The spherical indenter is penetrates into
the mould surface at the time of testing.
The depth of penetration w.r.t. the flat
reference surface of the tester.
• Mould hardness number = ((P) / (D –
(D2-d2))
• Where,
• P- Applied Force (N)
• D- Diameter of the indenter (mm)
• d- Diameter of the indentation (mm)

18. Silt content test
This is also a field test and to be conducted for every 20 cum.
The maximum quantity of silt in sand shall not exceed 8%. Fine
aggregate containing more than allowable percentage of silt shall be
washed so as to bring the silt content within allowable limits.

19. Grading of sand
The sand sieve analysis is carried out as
often as is required to maintain the correct
grading of sand that is to be used. The
grading of a sand aggregate for Ferrocement
is found by passing a representative sample
of dry sand through a series of BS sieves
Nos. 7, 14, 25, 52, 100 (or local equivalent
standard), starting with the largest sieve.

21. 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 form or in such quantities as to affect
adversely the hardening, strength or 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 not more than 5% by mass in ,natural
sand or crushed gravel sand and crushed stone sand.
• (b) Organic impurities when determined in colour of the
liquid shall be lighter in accordance with that specified in
the code.

22. Bulking of sand
Fine aggregate, when dry or saturated, has
almost the same volume but dampness causes
increase in volume. In case fine aggregate is
damp at the time of proportioning the
ingredients for mortar or concrete, its quantity
shall be increased suitably to allow for bulk
age. Table below gives the relation between
moisture content and percentage of bulking
for guidance only.

23. Bulking of sand
Moisture content (%) Bulking percentage (by volume)
2 15
3 20
4 25
5 30

24. Need for tests…
• Sands are usually washed by the suppliers to
remove clay, silt, and other impurities which, if
present in excessive amounts, result in poor
quality mortar.
• Impurities in the sand such as silt or organic
matter will weaken the final hardened concrete