This document provides an overview of the properties of concrete. It discusses the key ingredients of concrete including cement, fine and coarse aggregates, water, and admixtures. It explains that concrete is a composite material consisting of a binding medium within which particles of aggregate are embedded. The document also outlines the advantages of concrete such as its compressive strength and durability, and the disadvantages including its low tensile strength and cracking due to shrinkage. Finally, it lists the qualities of good concrete including workability, strength, density, and resistance to wear and tear.

1. Properties of Concrete (CE-203)
By:
Engr. Rameez Sohail
Lecture # 01
Department of Civil Engineering

2. Properties of Concrete
• Credit Hours 3 ( 2+1)
• Semester Weeks 16/18
• Evaluation/Grading
– Home Assignments
– Quiz test, unannounced
– Midterm test
– Attendance
• Semester Exam
2

3. What is Concrete?.
• Concrete is word of Latin derivation ( con – together ) ( crete
– to grow ) and its history can be charted from 3000 BC.
• It is a composite material that consists essentially of a binding
medium (Cement, Lime) within which are embedded particles
or fragments of aggregate(Coarse & Fine Aggregates).
• Concrete is often looked upon as “man made rock”.
Section cut from Hardened
Concrete
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4. Concrete Ingredients
☞Cement /Lime - Binder
☞Aggregate - sand, gravel, crushed rock
 Fine aggregate ----- Sand
 Coarse aggregates ----crushed rock
☞Water
☞Admixtures - when necessary
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5. Cement
A mixture of inorganic materials that sets and develops strength
by chemical reaction with water by formation of hydrates and is
capable of doing so under water.
Cement Powder Cement Bag
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6. Cement
Binds the aggregates into a solid mass
Imparts strength to concrete
Makes concrete impermeable by filling up voids in fine
concrete
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7. Aggregates
Granular materials, such as sand, gravel, crushed stone used with
cementing medium to form concrete or mortar.
Aggregates act as a relatively inexpensive inert filler, providing
stability against volume changes and influencing strength.
Fine Aggregate
Diameter< 4.75mm Coarse Aggregate
Diameter > 4.75mm
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8. Aggregates
Sand
Fills the voids within coarse aggregates
Assists in hardening of cement by allowing water to seep
through its voids
Minimizes shrinking and cracking of concrete
Economizes concrete by varying its proportion for strength
Coarse Aggregate
Acts as main filler, forms the main bulk mass
Binding material adheres on its surface
Imparts volumetric stability and durability to concrete
Increases crushing strength, resistance to wear and tear, and
water tightness of concrete
Economizes concrete since it is cheaper than cement
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9. Water
•It reacts with the cement to form binder that hardens and bonds
the aggregates together
•Lubricates the fresh concrete enabling it to be placed into
position and compacted.
•Good water is essential for quality concrete.
•It should be good enough to drink--free of trash, organic matter
and excessive chemicals and/or minerals.
•The strength and other properties of concrete are highly
dependent on the amount of water and the water-cement ratio.
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10. Concrete Ingredients
Admixtures
They are chemicals that can be added to the concrete
immediately before or during mixing and significantly change its
fresh, early age or hardened state to economic or physical
advantage
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11. Concrete Ingredients
• Admixtures
– Retarding agents – delay setting time
– Accelerators – set and acquire strength rapidly
– Air entraining agents
– Water proofing agents – pore filling, water repelling
– Pozzolanas – non-cementing, but forms lime
compounds which are cementing
– Pigments
– Workability agents
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12. Cement Concrete
• Coarse aggregate acts as a
filler.
• Fine aggregate fills up the
voids between the paste
and coarse aggregate.
• Cement in conjunction with
water acts as a binder.
• Admixtures aid the mobility
of the mixture by regulating
the setting environment and
time.
• (Setting & Hardening)
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13. Advantages of Concrete
Concrete is the most widely used construction material in the
world.
•It has relatively high compressive strength.
•It has better resistance to fire than steel, wood etc
•It has long service life with low maintenance cost.
•In some type of structure such as dams, piers and footing it is
most economical structural materials.
•It can be cast to take the shape required making it widely used in
pre-cast structural components.
•It yield rigid member with minimum apparent deflection.
•Concrete can be finished to produce surfaces ranging from glass-smooth
to coarsely textured, and it can be colored with pigments
or painted.
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14. Disadvantages of Concrete
•It needs mixing, casting and curing all of which affect the final
strength of concrete.
•The cost of formwork used to cast the concrete is relatively high.
•It has very low tensile strength.
•It has low compressive strength as compared to steel which lead to
large section of structural members.
•Minor crack develops in concrete due to shrinkage.
•It requires skill labor and supervision from mixing to finishing.
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15. Qualities of Good Concrete
Fresh Concrete
• Workability – easily workable
• Volume stability
Hardened Concrete
• Strength – compressive and tensile
• Durability – wind, rain, frost, temperature, chemicals and salts
• Density – 3,000 kg/m³ well compacted
• Water tightness – avoid corrosion of inside steel and leakage,
seepage in hydraulic structures
• Resistance to wear and tear – abrasive action in floors and
roads
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