Soil-Cement Pipe Bedding: Canadian River Aqueduct

Approximately 320 miles of pipeline on the Canadian River Aqueduct were bedded with a plastic soil-cement backfill. In this method, which was developed by the American Concrete Pipe and Construction Co., the pipe was set in a semicircular trench slightly larger than the pipe and the annular space was filled with plastic soil-cement. The bedding provides a direct transfer of the pipe load to the undisturbed foundation material; therefore, this method is suitable where the foundation is firm. The soil-cement consisted of 2 to 2-1/2 sacks of cement per cu yd of sand mixed with sufficient water to make it pumpable. Construction control was exercised to assure proper proportioning. Record compressive strength tests and laboratory tests were conducted to determine the general properties. A fall-sized test section showed the performance of the bedding to be satisfactory during a period of drying.