Thermal Performance of Fine‐Grained Soils

Abstract

Laboratory thermal probe tests performed on an AASHTO standard reference material (a silty clay) showed that the soil thermal behavior cor relates with the limit states of fine‐grained soils. Over 80 thermal resistivity measurements were made on specimens compacted to various densities and moisture contents. Results are presented which indicate that the optimum moisture content and the plastic limit can be correlated with the thermal be havior of fine‐grained soils. It was found that the minimum thermal resistivity and the critical moisture content occurred at the optimum moisture content when the soils were compacted using various compactive efforts. The knee of the thermal‐resistivity‐versus‐moisture‐content curve defines the critical moisture content. When the soils were compacted using a compactive effort of 1.42×105J/m3 (2,970 ft‐lb per cu ft), the minimum thermal resistivity occurred at the plastic limit of the AASHTO standard reference material. Also, indices are defined which allow comparison of the thermal behavior of fine‐grained soils.