This lecture introduces you to the idea of soil classification and why geotechnical engineers do it. Steps are provided to use the AASHTO classification system and the Unified Soil Classification System (USCS). Examples are performed.

Critical Questions to Consider:
1) Why do geotechnical engineers perform soil classification?
2) What are the differences between the AASHTO and the USCS systems?
3) Why don't we use the USDA system for engineering applications any longer?