Fabric of Field‐ and Laboratory‐Compacted Clay

The fabric of a medium plastic clay soil has been characterized by the distribution of the sizes of the void spaces in the soil. The soil has been compacted in the field by static—and vibratory—segmented pad rollers with different energies and water contents. Laboratory compaction by impact and kneading procedures was also conducted with different energies and water contents. Pore-size distribution was determined by mercury-intrusion porosimetry for each of the various as-compacted conditions created. Differences in the distributions were said to infer differences in soil fabric. Different energy levels created different fabric at comparable water contents relative to optimum. Only on the wet side of optimum for standard proctor energy could the fabric of laboratory and field compaction be labelled similar. It was concluded that for all other conditions the fabric of field compacted soil should be considered different from that produced by laboratory compaction. No laboratory procedure appears capable of always reproducing the fabric of field-compacted soil. Thus, there appears to be no substitute, today, for testing the field-compacted soil when behavior parameters are being determined.