According to Water-Cement Ratio Law, the strength of workable plastic concrete .............
Try it first: pick an option, then read the explanation.
Correct answer: D. All options are correct
Detailed Explanation: The Three Implications of Abrams' Law
Abrams' Law makes three bold claims about what does and does NOT affect concrete strength. All three are tested in this question.
Why D (All options are correct) is correct:Statement A — Depends on amount of water: More precisely, strength depends on the ratio of water to cement. Since at fixed cement content, more water means higher w/c and lower strength, the strength does depend on the amount of water used. This is true.
Statement B — Does not depend on cement quality: Abrams' Law states that for a given cement, at the same w/c ratio, the strength is constant regardless of quality differences — the law is calibrated per cement type. Within the same cement grade, strength depends only on w/c.
Statement C — Does not depend on cement quantity: This is the most distinctive claim. Two mixes with the same w/c ratio — one with 300 kg/m³ cement, another with 400 kg/m³ cement — have the same theoretical strength per Abrams' Law. The ratio matters, not the absolute quantity.
Summary of What Determines Strength per Abrams' Law
| Factor | Does it Affect Strength? |
|---|---|
| W/C ratio | YES — fundamental parameter |
| Amount of water (at fixed w/c) | No (ratio is what matters) |
| Absolute cement quantity (at fixed w/c) | No |
| Cement quality (grade) | No (calibrated per grade) |
| Mix workability | Must be workable for law to apply |
Key Concepts for Students
- Abrams' Law is about ratio only — not absolute quantities of water or cement.
- Two mixes with same w/c but very different cement contents achieve the same 28-day strength (all else equal).
- This is why mix design focuses on selecting the right w/c first, then proportioning cement and water to achieve required workability.