IMPROVING SUBDRAINAGE AND SHOULDERS OF EXISTING PAVEMENTS

Laboratory, test track and field results on channeling and pumping are presented. The influence of water on pumping and erosion of fine material from beneath the pavement surface is clearly shown. Methods for pavement drainage design in expansive soils and to resist the effects of frost action are presented. It is shown that the depth and location of subdrain systems will influence the water flux. Equipment and procedures for the maintenance and cleaning of subdrain pipes are discussed. A hydraulic jet unit for cleaning pipe subdrains has been discussed in detail.