Test: Textural Classification - Civil Engineering (CE) MCQ

Soil classification of composite soils exclusively based on the particle size distribution is known as textural classification.

Triangular classification of U.S. public road administration is a commonly used system for textural classification.

Since the textural classification is based on the percentages of sand, silt, and clay size making up the soil .such a classification is more suitable for describing coarse-grained soil.

to use the textural classification chart, for a given percentages of three constituents forming a soil, lines are drawn parallel to three sides of the equilateral triangle.

A triangle, having equal length of sides (i.e. Equilateral triangle) is used in textural classification chart.

HRB classification system, also known as public road administration (PRA) is based on both the particle-size composition and plasticity characteristics.

Highway research board classification system is also known as public road administration (PRA) system.

Based on HRB system, the soil is divided into 7 primary groups, designated as A-1, A-2…A-7.

As group index is a mean of rating the value of a soil as a sub-grade material
It can be used for finding the performance and quality of the soil.

Group index of a soil usually varies by
1. Liquid limit
2. Plastic limit
3. Amount of material passing through the 75-micron IS sieve.