Workability Classification – slump value of 60 mm If the measured slump of a concrete mix is 60 mm using the standard cone, how would you classify its workability for normal (non-flowing) concrete?

Introduction / Context:The slump test provides a quick field indicator of workability/consistency of fresh concrete. Interpreting a given slump value in terms of practical placement categories helps select mixes for slabs, beams, heavily reinforced members, and pumped or vibrated placements.

Given Data / Assumptions:

• Standard Abrams slump cone and test procedure.
• Conventional, non-self-compacting concrete.
• No special chemical admixtures altering slump retention beyond normal expectations.

Concept / Approach:

Typical ranges used on site are: very low (0–25 mm) for road pavements/roller-compacted types, low (25–50 mm) for lightly reinforced sections with vibration, medium (50–100 mm) for general RCC work, and high (>100 mm) for heavily congested reinforcement or pump mixes (with care to avoid segregation). At 60 mm, the mix sits comfortably in the medium workability band.

Step-by-Step Solution:

Verification / Alternative check:

Project specifications frequently call for 50–100 mm slump for general beams and slabs with internal vibration, aligning with this classification.

Why Other Options Are Wrong:

Very low/low are too stiff; high implies risk of segregation without admixtures; “None” is inapplicable because “Medium” matches well-established ranges.

Common Pitfalls:

Using slump as a proxy for strength; adding water to “fix” low slump rather than using admixtures; ignoring temperature and aggregate moisture effects on slump.

Final Answer:

Medium