Ece ppt

1. REINFORCED CEMENT CONCRETE
• Prepared By
• Mr. Ashok Kumar
• Lecturer in Civil Engineering
• Gpes Meham Rohtak

2. Chapter-I
Introduction
The word “concrete” originates from the Latin
verb “concretes”, which means to grow
together.
– Roadways/transportation systems
– Airstrips
– Infrastructure (bridges, dams, buildings)
– Harbor protection (break walls)
– Water distribution (pipes & conduit)

3. Advantage of Concrete
• We have the ability to cast desired shapes
– Arches, piers, columns, shells
• Properties can be tailored according to need (strength, durability, etc.)
• Ability to resist high temperatures
– Will maintain structural integrity far longer than structural steel
• Does not require protective coatings
• Can be an architectural & structural member at the same time

4. Properties of Quality Concrete
• Workability
• Durability
• Strength
• Chloride Penetration Resistance
• Abrasion Resistance

5. The Nature of Concrete
• It is a composite material
• Aggregates are 65% - 80% of the volume
– Fine aggregate: sand
– Coarse aggregate: stone
• Cement: General term & applies to any binder
– Portland cement
– fly ash
– ground slag
– silica fume
• Water

6. Concrete Microstructure

7. The Purpose Of The Aggregates
• Large aggregates:
– provide density (fill space)
– provide strength
• Fine aggregates:
– fill small voids between large
aggregates
– Increases strength of the cement
binder

8. The Cement Matrix
• Cement:
– produces a crystalline structure
– binds aggregates together
• Water
– causes chemical reaction to occur
– water/cementitious “react”
– produces workability

9. What is Portland Cement?
• Raw limestone, clay & gypsum minerals are ground
into powder & heated in kiln
(1600 ° C)
• Minerals interact at that temperature to form
calcium silicates (clinker)
• Available in five types, each with varying
performance characteristics and uses

10. Portland Cement Manufacturing
Process

11. Clinker

12. Hydration
• Portland cement becomes cementitious when
mixed with water
• This reaction is referred to as hydration.
• During hydration, a crystalline structure grows to
form bonds
• Hydration begins as soon as water meets cement
• Rate of hydration increases with increased
cement fineness

13. In Fact…….
• Concrete does not gain strength by “drying
out”
• Concrete must have continuous free access to
water to achieve its ultimate strength!!

14. Air Entrainment Admixtures
• All concrete containes “entrapped” air
• Large bubbles
• Large voids are undesirable for durability &
permeability
• Entrained air
• Bubbles are microscopic in size & distributed
through out concrete
• Increases durability by providing “escape route”
for freezing water as it expands

15. Entrained Air

16. Water Reducers (Super-Plasticizers)
• Increases viscosity
• Water can be reduced
• Results in higher strength and more durable
concrete due to reduced water

17. • colour –light wave length
• specific heat – the heat required to raise the
temperature of one gram of a substance by
one degree centigrade (J/kg K)
REINFOCEMENT MATERIAL
steel
1. Physical properties

18. • density – mass per unit volume expressed in
such units as kg/cm3
• thermal conductivity –rate at which heat
flows through a given material (W/m K)

19. Mechanical Properties
• melting point – a temperature at which a solid
begins to liquify
• electrical conductivity – a measure of how
strongly a material opposes the flow of
electric current (Ω⋅m)

20. Mechanical Properties
• tensile strength – measures the force required
to pull something such as rope,wire or a
structural beam to the point where it breaks
• ductility – a measure of how much strain a
material can take before rupturing

21. • toughness – the ability of a material to absorb
energy and plastically deform without
fracturing
• hardness – the property of being rigid and
resistant to pressure; not easily scratched

22. LOADING ON STRUCTURE AS PER IS 875
• Types of Loads on Structures and Buildings
• In a construction of building two major factors
considered are safety and economy. If the
loads are adjudged and taken higher then
economy is affected.
• So the estimation of various loads acting is to
calculated precisely. Indian standard code IS:
875–1987 and Other Structures specifies
various design loads for buildings and
structures.

23. Types of load on a structures
• Dead loads
• Imposed loads
• Wind loads
• Snow loads
• Earthquake loads
• Special loads

24. CHAPTER-2
METHOD OF RCC DESIGN
Working stress method
• Factor of safely for yield stress, allowable stresses are
less than ‘fy’.
• Pure elastic approach for analysis of structures under
working loads.
• Yielding or buckling never occurs at working loads
• Deformations are evaluated at working loads.

25. Limit state Method
• Acceptable limit for the safety and
serviceability requirements before failure
occurs is called a Limit state

26. • Partial safety factor for material (γm) for yield
and ultimate stress.
• Working loads are factored (increased) as per
partial safely factor (γf) causing Limit State of
strength.
• Post buckling and post yielding plays
important role in estimating capacity of
structural elements at Limit State.
• Deformations are evaluated at working loads.