This document provides an introduction to plain cement concrete and reinforced cement concrete (RCC). It defines plain concrete and lists its limitations, such as low tensile strength. RCC is introduced as a composite material that counters concrete's low tensile strength with steel reinforcement. The properties required of reinforcement are described. Advantages of RCC include high compressile strength and resistance to fire. The mechanism of composite action between concrete and steel is explained. Various types of loads, stresses, design methods, and design philosophies are also outlined.

1. Chapter 1
INTRODUCTION
Asst. Prof. Sushil Adhikari

2. Plain Cement Concrete Structures
• Plain concrete is defined as the mixture of
cement (including mineral admixtures), water
(including chemical admixtures), fine
aggregate and coarse aggregate, which is
obtained by mixing these ingredients in
certain proportion in order to achieve
required properties in fresh and hardened
state as well as durability requirement.

3. Limitation of PCC
• Concrete is Quasi-brittle Material.
• Low Tensile Strength.
• Concrete has Low Toughness.
• Concrete has Low specific strength.
• Formwork is Required.
• Long curing time.
• Working with cracks.
• Demands Strict Quality Control.

4. RCC
• Reinforced Cement Concrete is a composite
material in which concrete's relatively low
tensile strength and ductility are counteracted
by the inclusion of reinforcement having
higher tensile strength and/or ductility.

5. Requirement Properties of
Reinforcement
• High relative strength
• High toleration of tensile strain
• Good bond to the concrete, irrespective of pH,
moisture, and similar factors
• Thermal compatibility, not causing unacceptable
stresses in response to changing temperatures.
• Durability in the concrete environment,
irrespective of corrosion or sustained stress for
example.

6. Advantages of RCC
i. It has relatively high compressive strength.
ii. It has better resistance to fire than steel.
iii. It has long service life with low maintenance cost.
iv. In some types of structures, such as dams, piers and
footings, it is most economical structural material.
v. It can be cast to take the shape required , making it
widely used in pre-cast structural components.
vi. It yields rigid members with minimum apparent
deflection.
vii.Yield strength of steel is about 15 times the
compressive strength of structural concrete and well over
100 times its tensile strength

7. Mechanism of composite action of
reinforcement and concrete
• The reinforcement in a RC structure, such as a
steel bar, has to undergo the same strain or
deformation as the surrounding concrete in
order to prevent discontinuity, slip or
separation of the two materials under load.
• Maintaining composite action requires
transfer of load between the concrete and
steel.

8. Types of Loads
• Dead Loads
• Super Imposed Loads(Live Load)
• Wind Loads
• Snow Loads
• Seismic Loads
• Shrinkage, Creep and Temperature Effects

9. • Other Loads and Effects
– Foundation movement
– Elastic axial shortening
– Soil and fluid pressures
– Vibration
– Fatigue
– Impact
– Erection loads
– Stress concentration effect due to point of application
of load and the like

10. Types of Stresses
i. Compressive Stress
ii. Shear Stress
iii.Flexural Stress
iv.Tensile Stress
v. Bearing Stress
vi.Torsional Stress
vii.Thermal Stress
viii.Fatigue Stresses

11. Design Methods
• Design Steps:
– Idealization of Structure for analysis
– Estimation of Loads
– Analysis of structure to determine axial compression,
shears, bending moments and deflection
– Design of structural elements
– Check for strength and serviceability
– Detail structural drawings and schedule of reinforcement
bars
Philosophies for the design of RCC, pre-stressed and steel structures
– The working stress method
– The ultimate load method
– The Limit State Method
– Performance Based Design Method