ABSTRACT
This chapter considers only labour-intensive processes and products. The precast concrete industry has to be in the position of being able to offer the client anything that can be made in precast concrete varying from a 1kg garden gnome up to a 1000T bridge caisson. Concrete, generally from a central mixing area, has to be transported to the casting area, placed into the vibro-insulated mould and compacted by mould-fixing clamp-on vibrators. Post-tensioned anchor points concentrate a lot of punching shear stress in a very small locality and this is another reason for extra reinforcement in some cases. This reinforcement could be a spiral of high tensile steel bar surrounding the strand or wires. The surface crack width is no indication of the crack width at depth and in both cast stone and ordinary concrete drying shrinkage cracks taper with increasing depth into the product.
