Double hollow box section building block - is filled on site with concrete and has fracturable cavity dividing wall

摘要

The hollow building block is of precast concrete, being of a hollow box section open at the top and bottom. The blocks are laid dry jointed in courses to build a wall, accepting horizontal and vertical reinforcing bars, and being filled with e.g. in situ concrete to obtain a monolithic construction. A shallow trapezoidal tongue (4) and grooved joint provides for interlock at vertical joints, blocks including "tell tale" vents (17) and internally projecting bar locators (15,16). In addition a cavity (10) type intermediate cross-wall (5) is provided, aligning with fracture channels (11,12) on the exposed faces, and providing for the breaking of blocks into half bats on site. The vent holes (17) may be conical and may be plugged as the concrete rises above that level.