Sand

UNIT-1
TRADITIONAL BUILDING MATERIALS
“SAND”

WHAT IS SAND?
• 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.
• It is formed by the decomposition of
SANDSTONES due to various weathering
agents, like water, air, temperature variations.

COMPOSITION
• The composition of mineral sand is highly variable, depending on the local rock
sources and conditions.
• The bright white sands found in tropical and subtropical coastal settings are
eroded limestone and may contain coral and shell fragments in addition to
other organic or organically derived fragmental material, suggesting sand
formation depends on living organisms, too.
• The gypsum sand dunes of the White Sands National Monument in New
Mexico are famous for their bright, white color. Arkose is a sand or sandstone with
considerable feldspar content, derived from weathering and erosion of a (usually
nearby) granitic rock outcrop.
• Some sands contain magnetite, chlorite, glauconite or gypsum. Sands rich
in magnetite are dark to black in color, as are sands derived from
volcanic basalts and obsidian. Chlorite-glauconite bearing sands are typically green
in color, as are sands derived from basaltic lava with a high olivine content.
• Many sands, especially those found extensively in Southern Europe,
have iron impurities within the quartz crystals of the sand, giving a deep yellow
color.
• Sand deposits in some areas contain garnets and other resistant minerals,
including some small gemstones.

Sand as building material ! HOW
Sand is mixed with cementing materials for following reasons:-
• It sub divides the paste of cementing material into thin films and
allows it to adhere and spread.
• It prevents shrinkage of the cementing material.
• It adds to the density of the mortar.
• It allows carbon di oxide from the atmosphere to penetrate deeply,
and thereby improves setting.
• It reduces cost of concrete.
• It fills gaps between building blocks and spreads the binding
material easily.
• Silica of sand contributes to the formation of silicates, resulting in
formation of hard mass.

CLASSIFICATION OF SAND
SAND
FORMATION
PIT RIVER SEA
SIZE
FINE COARSE
GRAVEL
COMPOSITION
CLEAN SILTY CLAYEY

• PIT SAND
• RIVER SAND
• SEA SAND

PIT SAND
• This sand is obtained by forming pits in soil.
• 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.
• It serves as an excellent material for mortar
orconcrete work.
• Pit sand must be made free from clay and
other organic materials before it can be
used in mortar.
• A coating of oxide of iron over the sand grains
should be removed.

RIVER SAND
• This sand is widely used for all purposes. 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.
• The river sand is available in clean conditions.
• The river sand is almost white in color.
• It is mainly used for plastering.
• In north India , Yamuna banks are a great source
of River sand.

SEA SAND
• This is obtained from sea shores.
• It is brown in color and it also has the fine rounded
grain.
• As it is obtained from sea it contains salt, which is used
in attracting moisture from atmosphere.
• Such absorption causes dampness and efflorescence
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 structural purposes like
filling.

M SAND / ARTIFICIAL SAND
• It is also known as crushed sand.
• Due to shortage of natural sand, stones are
crushed into required size.
• It is a substitute for River Sand, fine
aggregates which manufactured by crushing
either granite or basalt rock using 3 stage
crushing process.
• It is also obtained as a by product when rocks
are crushed to get coarse aggregates.

ON THE BASIS OF SIZE OF
PARTICLES

• Based on grain sizes IS 383-1970 classifies sand to be used into four zones.
• For this sand should be sieved through a set of is sieves of sizes 10mm, 4.75mm,
2.36 mm, 1.18mm, 600 microns, 300 microns and 150 microns.
• The percentage of sand passing through sieve should be noted.
IS Sieve Percentage passing for
Grading Zone
I
Grading
Zone II
Grading
Zone III
Grading
Zone IV
10mm 100 100 100 100
4.75mm 90 – 100 90 – 100 90 – 100 90 – 100
2.36mm 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 microns 5 – 20 8 – 30 12 – 40 15 – 50
150 microns 0 – 10 0 – 10 0 – 10 0 – 15

FINE SAND
The sand passing through a sieve with clear openings of 1.5mm is
known as fine sand. Fine sand is mainly used for plastering.

COARSE SAND
The sand passing through a sieve with clear openings of 3.5mm is
known as Coarse Sand. Coarse Sand is generally used for masonry
work.

GRAVEL SAND
The sand passing through the sieve of 7.62mm is known as Gravelly
Sand. It is generally used for concrete work.

CLEAN SAND
•These are well graded sand containing mostly quartz
(SiO2)
•It is free from any organic or inorganic impurities
•It is perfect for construction purposes

SILTY SAND
•These are poorly graded sand with considerable amount
of Silt
•The size of silt particles are very small and form lump
•Not good for construction purpose

CLAYEY SAND
This sand have prominent clay fraction and plastic
fines.
Traditionally used for the construction of walls
Also used as mortar for bricks because of its high
adhesive property

USE OF SAND IN
CONSTRUCTION
1) Bricks work – Finest modulus of fine sand. The size of grains must be
between 1.2 – 1.5 mm. it is formed by mixing clay and sand with small
quantities of lime magnesia and iron oxide. Sand gives more shapely and
uniform texture to the bricks. An excess of sand, however render the bricks
too brittle and destroys cohesion. 25% of sand is said to be a good
proportion.
2) Plastering work – Finest modulus of fine sand which have grain size not less
than 1.5mm. It is usually mixed with cement in the ratio of 1:3 or 1:4.
It is the basic material for every construction. Most of the raw material for
construction consists of some ratio of sand.

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%.
Finest modulus of fine sand. The size of grains must be
between 1.2 – 1.5 mm. it is formed by mixing clay and sand
with small quantities of lime magnesia and iron oxide. Sand
gives more shapely and uniform texture to the bricks. An
excess of sand, however render the bricks too brittle and
destroys cohesion. 25% of sand is said to be a good
proportion.

• 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%.
3) Mortars and concrete work – Sand is used in
mortar and concretes for the following purposes :-
a) Strength – It helps in the adjustment of strength
of mortar or concrete by variation of its proportion
with cement or lime. It also increases the
resistance of mortar against crushing.

a) Bulk – It act as an adulterant. Hence, the bulk
volume of mortar is increased which results in
reduction of cost.
c) Setting – In the case of fat lime, CO2 is absorbed
through the voids of sand and setting of lime occurs
effectively.
d) Shrinkage – It prevents excessive shrinkage of
mortar in the course of drying. Hence, the cracking
of mortar during setting is avoided.
e) Surface area - It subdivides the paste of the
binding material into a thin film and thus, more
surface area is offered for its spreading and
adhering.

PROPERTIES OF GOOD SAND
 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
grains.
 It should not contain salts which attract moisture from
the atmosphere.
 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.

Tests
 Sieve test – Sand is filtered through sieve of suitable pore
size. If the residue left is more than the filtered sand then
the sand is of poor quality.
 Take some quantity of sand in water. Then, shake it
vigorously and allow it to settle down. If the clay and silt is
present in sand , its distinct layer is formed at the top of
water. The sand is acceptable if the amount of clay and
silt present is not more than 5% than the total mixture.
 To detect the presence of organic material in the sand,
add NaOH or Caustic Soda to it. If the colour changes to
brown, then the sand has organic impurities.

BULKING OF SAND
• Bulking is the increase in volume of a given mass of sand caused by the films of
water pushing the sand particles apart. Thus increase in volume of a given
mass of fine aggregates in the presence of water is known as Bulking.
• Compared to its dry or completely saturated volume, moist fine aggregate
tends to increase in volume due to capillary effect. The capillary action
between sand particles does not allow the particles to come closer to each
other. Thus this phenomenon causes Bulking.
• In completely dry or completely wet state there is no capillary action and
hence there is no, bulking. Thus the dry sand and the sand completely flooded
with water have practically the same volume. However in moist state
correction must be made for the volume of sand for use in concrete.
• For example, for a moisture content of 5 to 8 %, the bulking of sand can be as
much as 20 to 40% depending upon sand.
• However bulking is not considered when the mix design is based on Weight
and only to be considered when Volumetric proportioning of Sand is done.

Field test – Sample calculation
Moist Sand
Moist Sand

Issues of Bulking of sand ?
1) If proper measures are not accounted for
bulking of sand then, it results in increased cost
of concrete / mortar.
2) Also, it results in under sanded mixes [Less sand
than required] which are harsh and difficult in
working and placing.

Deleterious materials in sand
 Sand shall not contain any harmful impurities such as iron,
pyrites, alaklies, 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 IS 2386
(Part-II), 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 (Part –
II) than that specified in the code.

SUBSTITUES FOR SAND
• In place of sand, other materials such as crushed stone, burnt
clay or surkhi, cinder or ashes [FLY ASH & BOTTOM ASH] from
coal, coke dust etc.,. may be used to prepare MORTAR or
CONCRETE.
– The crushed stones are sharp and impart more strength to the
mortar. They are generally used for big construction projects like
concrete dams, bridges, etc.,. where sand in huge quantities is
not available near the place of work.
– They should however be properly screened to remove the stone
dust.
– The surkhi is the popular substitute for sand. It is obtained by
finely grinding burnt clay. It should be clean and free from any
impurities. It plays the same functions as those of sand. But in
addition, it gives strength and improves hydraulic property of the
mortar.
– However it disintegrates under the action of air and humidity, the
mortar with surkhi should not be used for external plaster or
pointing work.

SUBSTITUES FOR SAND
• Ok, I know that I can use Various substitutes for sand, but why should
I use them in the first place ????
– We are nowadays forced to replace fully or partially natural sand by
crushed sand. Severe restrictions are being imposed by many states
in India in quarrying sand from river beds for the following reason.
By mining sand from river bed, we lower the ground water level in
the river, in summer, when there is no flow in the river. This, in turn,
will lower the ground water level in all the neighbourhood. Hence,
in many rivers, nowadays, taking of sand in dry season is restricted.
Hence, in future, it will be necessary to plan to use ﬁne aggregate
obtained by crushing rocks or use a mixture of natural sand and
crushed rock aggregates for making concrete.
– However, the main objection of crushed rock fine aggregates is
that these aggregates are ﬂaky and badly - graded whereas natural
sand is well rounded and well graded. The latter requires less
water for the same workability and thus, gives better concrete.

SUBSTITUES FOR SAND
• However, with the introduction of better crushers which tend to
give better-shaped crushed fine aggregates, there will be more and
more use of crushed rock fine aggregate material in India. [WE GET
CUBICAL AGGREGATES TODAY FROM CRUSHED STONES]
• Crushed fine aggregates can also be made to give better concrete
than concrete made from river sand by proper design of mixes. The
harshness of these mixes can be removed by concrete additives.
Many ready-mix concrete companies have already started this
practice.
• CASE STUDY:
• The Pune-Mumbai express highway was a project where there was
difficulty in procurement of natural sand. This made the
construction company to use crushed fine aggregate for making
approximately 20 lakh cubic metres of concrete necessary for the
construction.

Transportation of sand
It is usually transported in trucks or trolleys from the digging
sites to the construction sites as it is required in bulk amount.
It is measured in cubic feet.
length
height

Sand

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