2.01 GENERAL: A. The Owner will furnish poles for direct embedment. B. Material used to backfill the upper one (1) foot of the excavation and surrounding area as indicated shall be as follows: 1. Cohesionless Materials: Includes gravels, gravel-sand mixtures, sands, and gravelly sands exclusive of clayey and silty materials – materials which are free-draining and for which impact compaction will not produce a well-defined moisture-density relationship curve and for which the maximum density by impact methods will generally be less than by vibratory methods. 2. Cohesive Materials: Includes silts and clays generally exclusive of sands and gravel – materials for which impact compaction and will produce a well-defined moisture-density relationship curve. 2.02 CONCRETE: A. As specified in Section 03 30 00, except as follows. 1. Minimum 28-day compressive strength of 3,000 psi. 2. Slump requirements for concrete placed in foundations shall be based on the construction method used, as follows: a. For dry uncased excavations: 4 to 6 inches. b. For temporarily cased excavations: 6 to 8 inches. c. For slurry excavations or placement of concrete under water: 7 to 9 inches. 2.03 SLURRY: A. Slurry shall consist of a mixture of bentonite (sodium montmorillonite conforming to API 13A) or anionic polymer and water to produce a slurry of sufficient density to maintain stability of the excavation walls and bottom and to facilitate removal of coarser grained soils from the excavation. B. Slurry shall be transported, premixed, and processed using equipment made specifically for these purposes. Mixing slurry within the foundation excavation is not permitted. C. Slurry properties such as density, sand content, pH, viscosity, etc., shall be tested and maintained per manufacturer's recommended ranges through the duration of excavation. 2.04 CASING: A. Temporary casing shall be steel and of sufficient strength to prevent collapse or cave-in of the excavation and prevent soil and water from entering the excavation during drilling, field observation, and backfill placement.
