MATERIALS

Aggregate Impact Value (AIV)

Percentage fines produced under standard impact — toughness of aggregate

Also calledaggregate impact valueAIVimpact value testaggregate toughness
Related on InfraLens
CODES
IS 2386
Definition

The Aggregate Impact Value, per IS 2386 Part 4, measures an aggregate's resistance to sudden shock/impact. A standard sample is subjected to 15 blows of a 13.5-14 kg hammer falling 380 mm; AIV is the percentage of the sample that passes the 2.36 mm sieve after the test. A lower AIV means a tougher aggregate better able to resist the dynamic impact of traffic and compaction.

It is a key acceptance test for road and concrete aggregates: IS 2386 / MORTH limit AIV to about ≤30% for concrete and surface/wearing-course aggregate, with relaxations (≤35-45%) for lower pavement layers. Together with the crushing value and Los Angeles abrasion, AIV screens out weak, easily-degradable stone that would break down under compaction and traffic, raising fines and fouling drainage.

Where used
  • Road + pavement aggregate acceptance (MORTH)
  • Concrete coarse-aggregate qualification (IS 383)
  • Quarry-source approval
  • Railway-ballast suitability
  • Comparing aggregate toughness across sources
Acceptance / threshold
Per IS 2386 Part 4; typically AIV ≤30% for concrete + wearing-course aggregate, with higher limits permitted for sub-base/lower pavement layers per MORTH.
Frequently asked
What does a low aggregate impact value mean?
A tougher, more impact-resistant aggregate. Lower AIV stone resists breakdown under traffic and compaction better, so it is preferred for concrete and pavement wearing courses.
What is the permissible aggregate impact value for concrete?
Generally ≤30% per IS 2386/IS 383 for concrete and wearing-course aggregate; lower pavement layers may allow up to ~35-45% per MORTH.
Related terms
Aggregate Crushing Value (ACV)
Percentage fines under a standard gradual crushing load — aggregate strength
Silt Content of Sand
Proportion of clay/silt fines in sand that weakens cement bond if excessive
Water Absorption (Aggregate & Brick)
Percentage water a porous material soaks up — a durability + mix-control index
Flakiness & Elongation Index
Percentage of flat/elongated particles — controls aggregate particle shape
Los Angeles Abrasion Value
Wear resistance of aggregate measured by tumbling with steel charge
Aggregates (Fine & Coarse)
Coarse (10-40mm) and fine (sand) aggregates per IS 383
Bulking of Sand
Volume increase of damp sand due to moisture films separating particles
Fineness Modulus
Single index of aggregate coarseness from cumulative sieve retention
Sand (River / M-Sand)
Fine aggregate. River sand or manufactured sand.
Setting Time of Cement
Time for cement paste to lose plasticity (initial) + fully set (final)