Question: 1. List the types of compactors that are available for compaction in confined areas.
2. A highway contractor has opened a cut in a fine silty sand (SM). Because of the cut location and lack of drainage, surface water has drained into the cut, leaving the material very wet. Rubber-tired scrapers are hauling material from the cut to an adjacent fill. The material is being placed in the fill in 8- to 10-in. (20- to 25-cm) lifts and compacted by a heavy shcepsfoot roller towed by a crawler tractor. It is apparent that the specified compaction (95% of standard AASHTO density) is not being attained. The sheeps foot roller is not "walking out," and the scraper tires am causing deep rutting and displacement of the fill material as they travel over it. What is causing the compaction problem? What would you suggest to the constructor to improve the compaction process?