Specifications
Generally, AS 2870 is used to obtain the required minimum dimensions and specifications for the depth, width and spacing of beams' slab thickness. The minimum strength of concrete used in slabs is N20 grade (20 MPa). It contains
20 mm aggregate and a slump of, typically, 80 mm.
The excavation depth of beams depends on:
- depth of adequate bearing soil below the surface
- depth of vegetation
- height of slab.
However, before the excavation of the slab begins, the entire area for the slab must be scraped. This removes grass and other organic matter which can decompose or shrink after a slab has been laid over it.
Typically a layer of approximately 100 - 150 mm is removed.