A. Prior to placing as pipe bedding, place the pipe to proper alignment and grade and support by blocking underneath the pipe to provide the minimum bedding depth shown on the Drawings. B. Place CDF bedding in such a manner and rate that the pipes being installed do not become buoyant or otherwise disturbed. C. Weather conditions: May be placed as pipe bedding if weather conditions are favorable. At the time of placement, CDF must have a temperature of at least 40 degrees F. Stop mixing and placement when the temperature is 38 degrees F or less and falling. Make each stage of placement of fill as continuous an operation as practicable. Do not place CDF on frozen ground. D. Remove groundwater in trench prior to placement of CDF. E. Contain trench sections to be filled at either end of trench section by bulkhead or earth fill. F. Place in the trench bottom in multiple/two lifts. Place the first lift uniformly on both sides of the pipe and allow to set prior to placing the second lift and subsequent lifts. The depth of the subsequent lifts shall be limited as necessary to prevent pipe buoyancy. G. Vibrate the fill by hand-operated mechanical compactor to remove voids underneath the pipe. H. Prior to the start of construction, demonstrate the workability, setting characteristics, and strength of the resultant mix through the preparation of a trial or test section of the pipeline I. The test section shall simulate, as nearly as possible, the field installation conditions in a typical lower trench area of the work. Modifications may require an additional test section for approval, as determined by the Project Representative. 3.02 MIXING A. Thoroughly mix the concrete slurry in a rotary drum or other approved type mixer. B. Continue mixing until the cement and water are thoroughly dispersed throughout the material. C. Place concrete slurry within 1 hour after mixing. 3.03 PLACEMENT A. Ensure the integrity of the completed pipeline system, conforming to the requirements of the trench bedding, and backfill details shown on the Drawings. B. Limit lift heights to avoid floating the pipe or other structures
