Unique Suspended Slab, Queensland

The slab had a series of voids in order to provide visibility into the area bellow it. In addition, there was also a series of soffits (600mm x 600mm x 50mm) in the bottom of the slab to allow for lights to sit flush with the surface.

These soffits meant that the bottom mat of steel required 80mm of cover from the bottom of the slab to provide 30mm of cover from the top of the soffit.  When taking into account the soffits and the slab voids, there was a total of 174 re-entrant corners, which led to some concerns (see below).

There were two primary goals.

1. Maintain a Class 1 finish
2. Minimize the risk of cracking on the bottom of the slabs due to:

• The large number of re-entrant corners spaced closely together
• The 80mm cover to the bottom steel due to the light box soffits.

Helix was used at a dosage of 18kg/m³ to provide added protection to the bottom of the slab and reduce the risk of visible cracks. At this dosage all top steel could be removed.

The job was a great success with both primary goals being achieved and no visible cracks in the slab what so ever, all while saving the client time and money!