Jason J. Henderson

Effects of particle size distribution and water content at compaction on saturated hydraulic conductivity and strength of high sand content root zone materials

Athletic field root zones are built with high sand content materials primarily to maintain drainage and macroporosity with compaction. However, these materials can also create problems due to their lack of strength. The objective of this study was to develop a better understanding of how particle size distribution and water content at compaction affect the strength and the hydraulic conductivity of high sand content root zones. One sand and one sandy loam textured soil were mixed in various proportions to produce seven mixtures. The sand/soil mixtures were subjected to four tests: standard Proctor compaction test, modified California bearing ratio, saturated hydraulic conductivity, and pore size distribution. The sand/soil mixtures were compacted at three water contents (5%, 9%, 13% kg kg−1) for mixes containing 2%, 5%, 7%, 8% silt + clay and at five water contents (5%, 7%, 9%, 11%, 13% kg kg−1) for mixes containing 10%, 12%, 15%, 19% silt + clay. For mixes containing 10% and 12% silt + clay, compacted at 5% water content, more than 100% increase in strength was observed over sand alone while maintaining hydraulic conductivity values of 19.0 and 8.5 cm h−1, respectively.