Double slab hollow concrete building block - has holes through lattice cross-arms for impregnating central passageways with e.g. bitumen

摘要

The hollow building block is used in the erection of sheathing concrete walls and comprises two parallel blocks at an interval apart, interconnected by one or more cross arm stems. There are holes through the cross arm stems for introduction of an impregnating substance which passes right through to the outside. This may be bitumen, synthetic resins or silicifying material. One of the slabs may be of lower height than the impregnated cross arm stems or both may be lower. Impregnation may be carried out about 24 hours after the block is made.