Pick up the incorrect statement from the following.
Try it first: pick an option, then read the explanation.
Correct answer: A. A rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive quantity of water
Detailed Explanation: Richness vs. Strength — The Incorrect Statement
Why A is INCORRECT: Statement A implies that a rich mix is always stronger than a lean mix that uses excessive water. While a lean mix with excessive water (high w/c) would indeed be weak, the underlying principle is that strength depends only on the w/c ratio (Abrams' Law), not on richness vs. leanness. A lean mix with carefully controlled low w/c would match or exceed the strength of a rich mix with poorly controlled (high) w/c. The statement incorrectly attributes strength to mix richness rather than the w/c ratio.Checking All Four Statements
| Statement | Verdict |
|---|---|
| A. Rich mix stronger than lean mix with excessive water | INCORRECT — strength depends on w/c ratio, not richness |
| B. Strength decreases as w/c increases | Correct — Abrams' Law |
| C. w/c < 0.45 → not workable, honeycombing | Correct — below workable range |
| D. Mechanical vibration compaction increases strength | Correct — expels air voids |
- Abrams' Law governs: strength depends only on w/c, not on cement content alone.
- A lean mix (low cement) with w/c = 0.40 can be stronger than a rich mix with w/c = 0.65.