Long-Term Benefits of Stabilizing Soil Subgrades

摘要

Chemical admixtures have been used extensively since the mid-eighties in Kentucky to improve bearing strengths of soil subgrades. Most pavements in Kentucky are constructed on clayey soils. Although short-term observations at a small number of sites showed that chemical stabilization worked very well, a need existed to perform a more comprehensive review and to assess the long-term benefits of this subgrade stabilization method. The main intent of this study was an attempt to address questions concerning bearing strengths, longevity, durability, structural credit, economics, and performance of pavements resting on soil subgrades mixed with chemical admixtures. In-depth field and laboratory studies were performed at fourteen roadway sites containing twenty different treated subgrade sections. Ages of the sites range from about 8 to 15 years. About 455 borings were made at the various sites. Air, instead of water, was used as the drilling media. In-situ CBR tests were performed on the treated subgrades and the untreated subgrades lying directly below the treated layers. Index tests and resilient modulus tests were performed on samples collected from the treated and untreated subgrades. Falling weight deflectometer (FWD) tests were performed.