Aggregate impact value (AIV) — suitability limits for different concretes For durability under impact and traffic, which of the following AIV limits are typically specified?

Introduction / Context:
The Aggregate Impact Value (AIV) assesses an aggregate’s resistance to sudden impact loading. Lower AIV indicates tougher aggregate, generally preferred for pavements and runways where repeated wheel loads impose dynamic effects. Knowing recommended AIV limits helps select aggregates appropriate to service conditions.

Given Data / Assumptions:

• AIV is measured by standardized impact testing.
• Service severity increases from building floors to pavements to runways.
• Lower AIV → higher impact resistance.

Concept / Approach:
For general building concrete, somewhat higher AIVs are tolerated because dynamic impact demand is lower. For road pavements and especially airfield runways, aggregates must be tougher; limits around 30 are often cited. Therefore, the graded set of limits (≈45 for buildings; ≈30 for pavements/runways) aligns with standard practice and forms the basis of aggregate acceptance for concrete exposed to traffic.

Step-by-Step Solution:

Verification / Alternative check:
Civil materials manuals list similar cutoffs, sometimes with modest local variations; the hierarchy remains consistent: the more severe the impact, the lower the acceptable AIV.

Why Other Options Are Wrong:

• Choosing any single limit overlooks the context-dependent nature of AIV acceptance.
• “None of these” contradicts established guidance.

Common Pitfalls:
Using a single AIV threshold for all applications; ignoring that skid resistance and abrasion (LA abrasion) also affect suitability.

Final Answer:
All of the above