- Reinforced concrete (RC)can also be termed as reinforced cement concrete (RCC) is a a mixture of concrete which has low tensile strength, and the property of ductility can be covered by providing the reinforcement having high tensile strength.
- The Reinforcement generally, But not necessarily consists of Steel bars (Rebar) and new usually implanted in the concrete before it gets set.
- It is one of the the key engineering material in terms of volume.
- This type of reinforcing construction are normally designed to prevent tensile stresses in the the portion of concrete which might cause cracking and structural failure.
- In modern era reinforced concrete have varied materials such as a Steel bars polymer or composite materials in co-occurrence with rebar.
- While under working loads reinforced concrete can be permanently stressed (i.e concrete in compression and reinforcement in tension) for improvement in behavior of final structure.
- Across world pre-tensioning and post-tensioning are the most common practice.
Properties of reinforcement for strong and ductile construction:-
- Relative strength should be high.
- Toleration of tensile strength should be high.
- Bonding with concrete should be good without affecting pH moisture and other factors.
- Thermal compatibility (i.e should not cause contraction and expansion with respect to change in temperature)
- Durability should be high respect of corrosion.
Use of reinforced concrete:-
- With the help of reinforced concrete different kind of structure and component can be built it such as slab walls beam foundation column and frames.
- It can be classified as precast and cast in place concrete.
- Reinforcement it is very essential component in the modern structure having concrete material.
- Designing the structure in optimum and efficient way is key to any building structure. Small changes can create remarkable effect on material cost ,ultimate strength and and end use of building.
Behavior of reinforced concrete:-
- Concrete is a combination of coarse aggregate such as stone or brick chips and fine aggregate such as sand or crushed stone with a paste of binding material which is Portland cement and water.
- When the cement is put together with small amount of water it generally hydrates and locking the aggregate into a hard structure.
- Harmful substances such as organic impurities silt clay lignite etc. should not present in the aggregate which is used for concrete.
- Generally concrete mix will have high resistance against compressive stress (4000psi) but due to bending it can break rigid lattice resulting in cracks and separatation of concrete.
- The
- Composite material made of of Steel which is good tension and reinforced concrete will resist not only compression but also bending and other tensile stresses.
- This composite section which have steel and reinforced concrete in compression and tension can made into any shape.
Reinforcement and terminology in beam
- If the bending moment is applied on the beam it resulted in a small curvature while a outer end (tensile face) of the curvature of concrete experiences tensile stress and in the inner side (compressive face) it experiences compressive stress.
- Singly reinforced beam is the beam in which concrete element it is is reinforced near the the tensile phase called as tension Steel and it's generally designed to resist the the tension in the member.
- A doubly reinforced beam is a beam in which along with tension reinforcement the concrete element is also near the compressive face to assist resist compression and reinforcement is called as compression Steel.
- When the architect limit the dimension of section the compressive moment (positive moment)cannot be resisted by compression zone of concrete also called as inadequate to resist so extra reinforcement has to be provided.
- Under reinforced beam can be called as where the the tension capacity in tensile reinforcement is less than compression capacity of the concrete and compression Steel.
- In this case, the reinforced concrete element is subjected to bending moment so the tension Steel will yields but still concrete failure hasn't reached.
- As the more tension yields and increases an under reinforced concrete Beam also yield in a in a way where large deformation present which doesn't give warning before its failure.
- For under reinforced concrete design can be governed by yield stress of Steel.
- An over reinforced beam can be defined as where tension capacity of the tension Steel bar is generally higher than the combined compression capacity of concrete and compression Steel.
- So as stated earlier the over reinforced concrete Beam fails by crushing of the compressors on concrete and before the tension zone steel yields as it does not provide any warning before failure as the failure is instantaneous.
- Balance reinforcement beam is a beam in which both the compressive and tensile zones reach yielding point and load is same also concrete will be crossed and tensile Steel I will also yield at the same time.
- This design criteria is one of the risky criteria because of the concrete crushers at the same time where tensile steel yield which will give very little warning before failure.
- To receive the warning of implementing collapse Steel reinforced concrete moment carrying element should normally designed as under reinforced.
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