Reinforced Cement Concrete, commonly known as RCC, is one of the most important subjects in civil engineering viva exams. Whether you are appearing for a diploma, degree, or site interview, RCC viva questions test both your basic concepts and practical understanding. This blog explains everything in easy English, making it ideal for last-minute revision.
What is RCC?
RCC is a composite material made by combining concrete and steel reinforcement. Concrete is strong in compression, while steel is strong in tension. Therefore, when both materials work together, the structure becomes safe and durable.
In simple words, RCC allows us to construct beams, slabs, columns, footings, and many other structural members.
Basic RCC Viva Questions and Answers
1. Why is steel used in RCC?
Steel is used because concrete cannot resist tensile forces. Steel bars take tension, while concrete resists compression.
2. What is the minimum grade of concrete used in RCC?
As per IS 456:2000, the minimum grade of concrete for RCC is M20.
3. What is the clear cover in RCC?
Clear cover is the distance between the outer surface of concrete and the nearest reinforcement bar. It protects steel from corrosion and fire.
4. What is the purpose of reinforcement?
Reinforcement controls cracks, resists tension, and improves ductility in RCC structures.
Important RCC Components (Viva Focus)
Cement
Ordinary Portland Cement (OPC) or Portland Pozzolana Cement (PPC) is commonly used in RCC works.
Aggregates
- Fine aggregate: Sand
- Coarse aggregate: Crushed stone (20 mm is most common)
Reinforcement Steel
TMT bars such as Fe 415, Fe 500, or Fe 550 are widely used in RCC construction.
RCC Structural Elements – Viva Questions
RCC Beam
A beam carries bending loads and transfers them to columns.
Common viva question:
Why are main bars placed at the bottom of a simply supported beam?
Because the bottom portion is under tension.
RCC Slab
A slab is a flat structural element used for floors and roofs.
Example:
One-way slab is provided when the length-to-breadth ratio is greater than 2.
RCC Column
Columns carry axial loads from slabs and beams to the foundation.
Key viva point:
Columns fail mainly due to buckling.
RCC Mix Design – Simple Explanation
Mix design means calculating the correct proportion of cement, sand, aggregate, and water to achieve required strength.
Example:
For small works, nominal mix like 1:1.5:3 is used.
For important RCC structures, design mix is preferred.
RCC Curing – Viva Importance
Curing is the process of keeping concrete moist to gain strength.
Minimum curing period:
- OPC: 7 days
- Blended cement: 10 days
Without proper curing, RCC may develop cracks and low strength.
Common RCC Defects (Viva Questions)
- Honeycombing – due to poor compaction
- Segregation – due to excess water
- Cracks – due to shrinkage or improper design
Case Study: RCC Beam Failure on Site
On a residential site, an RCC beam developed cracks within 15 days. Investigation showed:
- Poor vibration during concreting
- Inadequate curing
- Use of excess water
Lesson for viva:
Proper workmanship is as important as good design in RCC construction.
RCC Codes and Standards (Must for Viva)
- IS 456:2000 – Plain and Reinforced Concrete
- IS 1786 – Steel reinforcement
- IS 10262 – Mix design
- IS 875 – Loads on structures
Mentioning standards creates a strong impression during RCC viva.
Practical RCC Viva Questions
- Why lapping is not provided in columns at floor level?
- What is development length in RCC?
- Difference between working stress method and limit state method
- Why shear reinforcement is required?
RCC Viva Tips for Students
- Always explain answers with simple logic
- Use site examples wherever possible
- Quote IS codes confidently
- Draw neat sketches if allowed
Conclusion
Preparing for civil engineering viva questions (RCC) becomes easy when concepts are clear and practical. This blog covers theory, site knowledge, standards, examples, and common viva questions in one place. If you revise this guide properly, you can confidently face any RCC viva in college exams or job interviews.
Frequently Asked Questions (FAQs)
Q1. Why RCC is preferred over plain concrete?
Because RCC can resist both compression and tension.
Q2. What happens if clear cover is less?
Steel may corrode and reduce the life of the RCC structure.
Q3. What is the lifespan of RCC buildings?
With proper design and maintenance, RCC structures can last 75–100 years.
Q4. What is the role of stirrups in RCC beams?
They resist shear forces and hold main bars in position.