Gradation can be defined as the process of arranging aggregates based on their size. Sieve analysis is carried out to determine the particle size distribution. Aggregates are an important part of the construction industry as they constitute a significant portion of concrete mixes. Depending on the correct gradation of aggregates, the quality and performance of the concrete is affected.
The best gradation produces the maximum density with lesser air voids.
Trenchlesspedia Explains Gradation
The gradation or particle size distribution of aggregates will determine the performance of the concrete mix in whichever situation it is used. Concrete is used for a variety of purposes from making pavement to filling up annular gaps between borehole walls and the pipe. Gradation helps determine stiffness, workability, durability, permeability, stability, friction resistance and susceptibility to moisture.
To get the maximum density, the particle arrangement should have smaller particles packed between the larger aggregates. This helps reduce the voids between the different sized aggregate and sand and increases the contact between particles.