Augercast piles are installed by drilling with a hollow stem, initially plugged, continuously flighted auger to design depth.The plug is then ejected and a high strength sand-cement grout is pumped into the hole as the auger is slowly withdrawn. Dependant on the injection and withdrawal rates, the grout may displace the existing soils optimizing bearing properties.
Limited reinforcing steel can be installed or vibrated down into the fresh grout once completed. The resulting grout column subsequently hardens and forms an augercast pile. Pile diameters of 12 to 18 inches are most common for augercast type piles, with the diameters up to about 36 inches possible. Augercast pile advantages include not requiring casing or slurry for their construction, speed of installation and cost. Augercast piles have the disadvantages of being constructed at smaller diameters and thus lesser capacities, and have limited reinforcement capabilities.