Pick up the correct statement from the following
Correct Answer: D. All options are correct
📚 Detailed Explanation: Three Correct Statements on Concrete Mix
Why D (All options correct) is correct:
A — Correct: “Increase in water must be accompanied by increase in cement.” This is mix design principle. If you add water without extra cement, w/c rises and strength drops. To maintain target w/c and strength, cement must increase proportionally with any water increase. This is the basis of constant-w/c mix adjustments in IS 10262.
B — Correct: “Angular and rough aggregates reduce workability.” Angular, crushed aggregates have sharp edges and rough surfaces — both create high inter-particle friction and mechanical interlocking, requiring more effort (or more water) to achieve the same workability as rounded aggregates.
C — Correct: “Large aggregates increase workability due to less surface area.” Larger aggregate particles have a smaller total surface area per unit volume (or per unit mass). Less surface area = less water needed to wet all surfaces = more free water available for lubrication = higher workability for the same water content.
A — Correct: “Increase in water must be accompanied by increase in cement.” This is mix design principle. If you add water without extra cement, w/c rises and strength drops. To maintain target w/c and strength, cement must increase proportionally with any water increase. This is the basis of constant-w/c mix adjustments in IS 10262.
B — Correct: “Angular and rough aggregates reduce workability.” Angular, crushed aggregates have sharp edges and rough surfaces — both create high inter-particle friction and mechanical interlocking, requiring more effort (or more water) to achieve the same workability as rounded aggregates.
C — Correct: “Large aggregates increase workability due to less surface area.” Larger aggregate particles have a smaller total surface area per unit volume (or per unit mass). Less surface area = less water needed to wet all surfaces = more free water available for lubrication = higher workability for the same water content.
Verification of All Three Statements
| Statement | True/False | Principle |
|---|---|---|
| A. More water needs more cement | True | Constant w/c = proportional cement increase |
| B. Angular aggregates reduce workability | True | High surface friction and interlocking |
| C. Larger aggregates increase workability | True | Lower surface area = less water demand |
- All three are fundamental principles of concrete mix design and aggregate science.