Concrete Workability – identify the single correct statement Consider the following statements about fresh concrete and slump/workability. Select the one statement that is correct and most generally true for site practice.

Introduction / Context:
Workability describes how easily freshly mixed concrete can be placed, compacted, and finished without segregation or bleeding. The slump test is a rapid field indicator of workability. Understanding what specific slump values imply helps supervisors judge moisture control, sand proportioning, and suitability of mixes for different members.

Given Data / Assumptions:

• Conventional slump cone test for normal-weight concrete.
• No chemical admixtures unless stated; ordinary site concrete.
• “Dry mix” refers to very low water content and harsh consistency.

Concept / Approach:
In the slump test, a very dry, harsh mix does not subside when the cone is lifted, giving a slump of about zero. Higher slump generally reflects more fluidity, usually due to higher water content or water-reducing admixtures. However, diagnosing sand deficiency strictly from high slump is incorrect; lack of fines usually reduces cohesion and can even reduce measurable slump for the same water content.

Step-by-Step Solution:
Link “dry mix” to measurable effect: with inadequate water, concrete retains its shape → slump ≈ 0.Check other claims: “higher workability = sand deficiency” is not a reliable rule; grading affects cohesion more than pure workability.“Zero slump unsuitable for high strength” is false; high-strength concrete often uses low w/c ratios and may have low slump unless superplasticized.Therefore, the universally correct statement is that a dry mix yields zero slump.

Verification / Alternative check:
Site practice correlates zero slump with very stiff concrete used for road kerbs or roller-compacted placements; the measurement consistently reads near zero.

Why Other Options Are Wrong:

• (a) Higher workability can come from admixtures or optimized grading, not only excess moisture.
• (b) Sand deficiency tends to decrease cohesiveness; it is not a diagnostic for “higher workability”.
• (d) High strength is compatible with low slump; superplasticizers decouple strength from slump.
• (e) Cannot be true because (b) and (d) are incorrect.

Common Pitfalls:
Using slump alone to approve mixes; always consider segregation risk, placement method, and admixture effects. Control water content by mass, not by visual judgement.

Final Answer:
If the concrete mix is dry, the slump is zero