SIEVE ANALYSIS AND AGGREGATE IMPACT VALUE TEST

SIEVE ANALYSIS

Sieve analysis is an analytical technique used to determine the particle size distribution of a granular material with macroscopic granular sizes. The technique involves the layering of sieves with different grades of sieve opening sizes. The finest sized sieve lies on the bottom of the stack with each layered sieve stacked above in order of increasing sieve size. When a granular material is added to the top and sifted, the particles of the material are separated into the final layer the particle could not pass.

Commercial sieve analyzers weigh each individual sieve in the stack to determine the weight distribution of the particles. The base of the instrument is a shaker, which facilitates the filtering.

Sieve analysis is important for analyzing materials because particle size distribution can affect a wide range of properties such as the strength of concrete, the solubility of a mixture, surface area properties and even their taste.

AGGREGATE IMPACT VALUE TEST

Scope & significance: Aggregate Impact Value

The aggregate impact value gives a relative measure of the toughness or the resistance of aggregate sudden shock or impact is not proportional to the resistance to a slowly applied compressive load. Aggregate Impact Value

Aggregate Impact Value:

  • AIV is the percentage of fines produced from the aggregate sample after subjecting it to a standard amount of impact. Aggregate Impact Value
  • The standard amount of impact is produced by a known weight, i.e. a steel cylinder, falling a set height, a prescribed number of times, onto an amount of aggregate of standard size and weight retained in a mould.
  • Aggregate Impact Values, (AIV’s), below 10 are regarded as strong, and AIV’s above 35 would normally be regarded as too weak for use in road surfaces.
  • Aggregate Impact Values and Aggregate Crushing Values are often numerically very similar, and indicate similar aggregate strength properties. Aggregate Impact Value

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