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: Water 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. REINFOCEMENT MATERIAL steel 1. Physical properties
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)

18. density – mass per unit volume expressed in such units as kg/cm 3
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.
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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.