Volume 25, Issue 1 (March 2002)
Empirical Performance Classification for Cohesive Embankment Soils
In response to recent evidence of poor highway embankment quality caused in part by improper soil identification and placement during construction, field-testing and laboratory analysis were conducted to develop a simple performance-based soil classification system that can be conducted in a field laboratory. Development of the Empirical Performance Classification (EPC) system is based on swell potential and frost susceptibility relationships of soils derived from liquid limit, plasticity index, and fines content (≤ 75 µm). From these parameters the EPC system is used to classify soils into one of three categories: select, suitable, or unsuitable. This paper presents the background for the development of this system and procedures for its use. A field trial in Iowa indicates that Iowa Department of Transportation field personnel can effectively use the EPC system to classify soils in the field and to link design with construction activities better. Increased field soil classification is expected to improve long-term performance of cohesive earth embankments.