ABSTRACT
Compaction is a process whereby a soil is densified by expending energy on it. Traffic compaction results from the work done as vehicles travel over the surface, not with the specific purpose of compacting it, but in order to discharge some other function, e.g., to dump more material. Roller compaction arises from the deliberate trafficking of a surface by a vehicle specifically designed to expend energy in compaction, i.e., a compactor or roller. The energy input may arise simply from the weight of the roller moving down as it compresses the fill, or there may be an additional energy input, e.g., resulting from the repeated toppling of the roller as with an impact roller or the gyration of an eccentric weight as with a vibrating roller. Poundingwith a fallingweight is a fourth method of compaction that is sometimes used. Figure 4.1 illustrates these four ways of expending compactive energy. In addition, rollers may have a variety of surfaces that contact the soil in different ways. Smooth wheeled, footed or pneumatic tyred rollers as well as grid-rollers are all used. This chapter will describe the generic technology of compaction and then proceed to describe specific aspects relating to the compaction of residual soils.
