• Vital construction material
• The Mixture of Portland cement, water,
aggregates and in some cases, admixtures.
• The cement and water form a paste that
hardens and bonds the aggregates together.
Concrete is one of the most commonly used
Concrete is a versatile material that can
easily be mixed to meet a variety of special
needs and formed to virtually any shape.
Main Ingredients of concrete
• For small & important works mixing of concrete is done by
• Hand mixing of concrete should be done on
hard,clean,water tight surface like a concrete floor or
• It requires about 10% more of cement than what is
required in Machine mixing.
• For large scale work concrete mixers are used.
• The interval of time for which the concrete should be
mixed depends upon the quantity of mixer.
• Time ranges from 1.5 to 3 min.
• Types ofconcrete mixer:-1)Rotary mixer 2)Tilting mixer
Types Of Grade
Mix Portion (Cement : Sand :
1 : 5 :10
1 : 1.5 : 3
M refers to the Mix and the number indicates the specified
compressive strength of that Mix at 28 days expressed in
• The process of keeping concrete wet to enable
it to attain full strength is known as curing.
• The objective of curing is to prevent loss of
moisture from concrete due to evaporation or
because of any other reasons.
• Curing should be done for a period of three
weeks but not less then 10 days.
• To do curing, any one of the following method
can be used.
i. The surface of concrete is coated with a layer
of bitumen or similar other waterproofing
compound which gets into the pores of
concrete and prevent loss of water from
ii. Concrete surface is covered with waterproof
paper or with a layer of wet sand. It could also
be covered with gunny bags.
• High compressive strength
• More economical than steel
• Not subjected to corrosive wreathing
• Versatile material in building construction
• Hard and durable
• Water tightness & strength
• Poor tensile strength
• Develops shrinkage stresses
• Requires skill and supervision
• Cracks may occur & strength of concrete may come down
• Repairing is difficult
• Curing time of concrete is more
• Sand is an important building material. IT CONSISTS OF
SMALL ROUNDED OR ANGULAR GRAINS OF SILICA
sio2 AND IS FORMED BY THE DECOMPOSITION OR
DISINTEGRATION OF SAND STONE UNDER THE
ACTION OF WEATHER SUCH AS WIND,RAINS FORST
• It forms a major ingredient in concrete , lime mortar ,
cement mortar etc.
• It abundantly occurs in nature.
• Sand is formed by weathering of rocks
• Sand can be divided into three main class
depending upon the source from it is obtained
• 1)pit sand
• 2)river sand
• 3)sea sand
• It is obtained by digging pits in the soil. It is excavated
from A depth of about 1.2 M from the ground level.
• This soil consists of sharp angular grains, which are free
from silt, clay, salts etc.
• Clean pit sand forms an excellent material for mortars
• This sand is widely used for all purposes, it is considered
to be best sand suitable for important works
• It is obtained from the banks or beds of rivers and it
consists of fine rounded grains.
• The river sand is available in clean conditions and is
almost white in color.
• Sea sand is obtained from the sea shores. It is also
clean having rounded particles.
• Sea sand is light brown in color. Sea sand is always
available in combination with certain injurious salts and
hence sea sand is unsuitable for making mortar or
• Sea sand increases the setting time of cement.
• Hence, it is the general rule to avoid use of sea sand for
• According to the particle size the sand can be classified as coarse
sand, medium sand and fine sand
• 1)coarse sand:
• Sand particle passing through 3.175 mm SIEVE IS TERMED AS
COARSE SAND. It is generally used for masonry work.
• 2)medium sand
• Sand particle passing through 2.36 mm SIEVE WILL BE CALLED
MEDIUM SAND. It is used for plastering.
• 3)fine sand
• Sand particle passing through 1.5875 mm SIEVE WILL BE
CALLED FINE SAND. It is used for plastering.
• Good sand should possess the follwing
• It should be chemically inert
• It should have sharp angular grains
• The size of grains should be between 4mm and 6mm
• It should be strong and durable
• It should be not conain salts wich attract moisture from
Following are the various uses of sand
It is used for making lime mortar
It is used for making cement mortar
It is used for making cement mortar
It is used for making cement concrete
It is used for masonry work , plastering and pointing
– Granular material of
such as sand, gravel,
shale, slag or
• Coarse Aggregate:
retained on the
4.75mm (#4) sieve
Completely passing through
the 9.5mm (3/8”) sieve
– Igneous (solidification of
– Sedimentary (consolidated
– Metamorphic (preexisting
rock changed by
temperature or pressure
– Material that covers
the bedrock which
may be cm or km in
– Boulders, cobbles,
gravel, sand, silt, clay
• Group I –Glassy
Optical Properties •
React with Acids
Luster (dull, glassy)
– Quartz, Obsidian
Group II – Dull, Fine Grain
– Scratch with a knife
• Shale, limestone
– Hard - Chert, Basalt
Group III - Granular
– Scratch with a knife
• Limestone, dolomite
• Granite, Gabbro
Good adhesion with brick,stones etc.
Resist penetration of rain water.
Should be cheap, durable and workable.
Should be set quickly
Joints formed by mortar should not develop
Maintain their appearance for long period
•As per binding material:•Cement Mortar
•As per Nature of application:•As per Density of the Mortar
Uses of MORTAR
• Bind bricks or stone
• Used in plaster work as
• Joints covered by
• Bituminous binders used in pavement construction works
includes both bitumen and tar.
• The bitumen is a binding material which is present in asphalt.
It is also sometimes called the mineral tar.
• Bitumen is a petroleum product obtained by the distillation of
petroleum crude whereas road tar is obtained by the
destructure distillation of coal or wood.
• It is chemically hydrocarbon.
• The bitumen is black in colour and it is obtain in solid or
• Bituminous material are used for various engineering
purposes such as dam roof courses,water proff layer for tanks
• they are very commonly used in highway constructions n
Bitumen is available in variaties of types n grates. Thus
bitumen material is classified as bellow:
• It is defined as a natural or artificial
mixture in which bitumen is associated
with inert mineral matter
• it is black or brownish black in color.
• it is also one off the most important
bituminous material which is produced
by destructive distillation of organic
material such as coal, oil, peat, and
• It is black to dark brown in color.
• For cold application as in case of
repairing cracks in roofs, floors etc.
asphalt mixed with the liquid solvent
and then it is called cut black asphalt.
• It is obtained by fluxing asphatic
bitumen in presence of some suitable
liquid distillates of cold tar or
• For cold application asphalt is
available in the form of emulsion.
• it is the liquid product containing
bitumen to a great extend in an
• The bituminous material are also called binders
which are used in combination with mineral
aggregate in road construction. Their functions
are as follows:
1. BINDING EFFECTS: the bitumen binds the
surface particles together.
2. CUSHION: it acts as a cushioning material on
the surface absorbs impact friction etc due to
movements of vehicles on road.
3. SEALING OF SURFACE: When used with the
dense graded and angular material. It seals the
surface of the road against ingress of water.
4. RESISTANCE TO WEATHERING AGENTS: If
the bituminous material is selected properly
and is used in road construction can resists
effectively the actions of weathering agents like
the wind and the sun.
1. the viscosity of the bitumen at the time of
mixing and compaction should be adequate.
2. It should posses sufficient adhesion with the
aggregate in the mix in presence of water.
3. The presence of water the bitumen should not
strip off from the aggregate.
4. The bituminous material should not be highly
• Book:– Elements of CIVIL Engineering
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