This document discusses several particle size classification systems used in soil science and civil engineering. It outlines the USDA, USCS, and AASHTO systems, providing flow charts for classifying soils as coarse-grained or fine-grained based on particle size. It also mentions using a plasticity chart and provides a generalized comparison of the Unified and AASHTO classification approaches.

1. 1. Particle Size Classification of
Classification Systems
US Department of Agriculture (USDA) System

2. Unified Soil Classification System (USCS)
Flow chart for classifying coarse-grained (gravel or sand)
soils(more than 50 percent retained on No. 200 sieve).

3. Flow Chart for classifying fine-grained (silt or clay) soil (50 percent or more passes No.200
sieve)
Plasticity Chart

4. AASHTO Classification System

5. A generalized comparison of the Unified and AASHTO systems is presented.