This topic includes information related to underwater concrete placed during construction. Underwater concrete is placed using a tremie, a vertical pipe with a funnel shaped top. Mixtures for underwater concrete are designed for a continuous pour and prevention of cement washout. Additives are used in conjunction with cement and aggregate to increase underwater concrete strength.
03 37 00 Specialty Placed Concrete
There are several Specialty, or non-traditional, methods of Placing Concrete. These methods can offer economic advantages in terms of site preparation, the need for accessories and equipment, and reduced labor costs. Properly applied, Shotcrete, a sprayed concrete, is a durable construction material that bonds strongly with earth, rock, steel and existing concrete. Shotcrete is easily applied, its formwork assemblies are often simpler than in conventional placement, and less material is used, since the layers of sprayed concrete are thinner. Pumped Concrete and Pneumatically Placed Concrete also involve the delivery of concrete as a spray from either a dry or wet mix. Both methods utilize pumps, primarily the mechanical type for the pumped concrete, whereas pneumatic placement uses compressed air. For sites that are difficult to access, or at which space is limited, these methods are practical alternatives to conventional concrete placement.
This topic includes information related to shotcrete placed during construction. Shotcrete is a wet premixed concrete that is cast onto vertical and overhead surfaces by a compressed air hose. Shotcrete does not require formwork and can be reinforced with steel rods, mesh or fibers.