Effect of aggregate characteristics: The strength and overall quality of concrete are significantly influenced by which aggregate properties?

Introduction / Context:
Aggregates occupy 60–80% of concrete volume. Their characteristics strongly affect workability, water demand, paste requirement, strength, and durability.

Given Data / Assumptions:

• Normal-weight concrete with natural or crushed aggregates.
• Standard water–cement ratio and compaction.

Concept / Approach:
Well-graded aggregates reduce voids and paste demand. Finer surface area increases water requirement but can improve packing if well graded. Angular, rough particles increase interlock and potential strength but reduce workability; rounded particles improve workability but may lower interlock. Surface texture affects bond between paste and aggregate and hence tensile/compressive behavior.

Step-by-Step Solution:
Assess grading → controls void content and paste demand.Evaluate surface area → impacts water and admixture demand.Consider shape → influences packing/workability and mechanical interlock.Check texture → governs bond strength at the ITZ (interfacial transition zone).All listed properties influence quality → choose “All of the above.”

Verification / Alternative check:
Mix-design methods (e.g., ACI, BIS) explicitly incorporate grading, shape, and texture adjustments.

Why Other Options Are Wrong:
Any single property alone cannot fully define performance; they act together.

Common Pitfalls:
Assuming stronger aggregate always means stronger concrete; ignoring workability and compaction effects.

Final Answer:
All of the above.