Consider the below statements: i. Size and shape of aggregates influence workability. ii. As w/c increases, strength increases. iii. Maturity of concrete is independent of curing temperature. Which is/are correct?
Correct Answer: A. Only i
📚 Detailed Explanation: Evaluating Three Statements on Concrete
Why A (Only i) is correct:
Statement i — TRUE: Aggregate size and shape are primary factors affecting workability. Larger aggregates reduce specific surface area (better workability at same water content); rounded aggregates reduce friction (better workability); angular/flaky aggregates increase friction (lower workability).
Statement i — TRUE: Aggregate size and shape are primary factors affecting workability. Larger aggregates reduce specific surface area (better workability at same water content); rounded aggregates reduce friction (better workability); angular/flaky aggregates increase friction (lower workability).
Statement ii — FALSE: Higher w/c ratio decreases compressive strength (Abrams' Law: strength is inversely proportional to w/c). Higher w/c increases workability but reduces strength.
Statement iii — FALSE: Maturity of concrete (the concept used to predict strength development) is the product of temperature × time. Temperature absolutely affects maturity — higher curing temperature = faster hydration = higher early maturity. Cold curing slows strength gain.
Quick Verdict on Each Statement
| Statement | True/False | Key Reason |
|---|---|---|
| i. Shape/size affects workability | TRUE | Surface area and friction govern workability |
| ii. Higher w/c → higher strength | FALSE | Abrams' Law: inverse relationship |
| iii. Maturity independent of temperature | FALSE | Maturity = Σ(T × t); temperature is critical |
- Only statement i is true — aggregate characteristics affect workability.
- Maturity concept: M = Σ(T − Tdatum) × Δt; temperature is a multiplying factor.