The composite slabs are made of BubbleDeck type slab elements with spherical gaps, poured in place on transversal and longitudinal directions. By introducing the gaps leads to a 30…50% lighter slab which reduces the loads on the columns, walls and foundations, and of course of the entire building. These slab elements have a bottom and an upper concrete part connected with vertical ribs that go around the gaps. The reinforcement of the plates is made of two meshes one at the bottom part and one at the upper part that can be tied or welded. The distances between the bars correspond to the dimensions of the bubbles that are to be embodied and the quantity of the reinforcement from the longitudinal and the transversal ribs of the slab. The two mashes are connected after placing the spheres into places in order to form a rigid shell. The bubbles are made by embodying high density polypropylene in the concrete, arranged according to the project and placed between the reinforcement meshes. The material that are made of don’t react chemically with the concrete or the reinforcement, it has no porosity and has enough rigidity and strength to take over the loads as much as from the pouring of the concrete as from the subsequent phases of this process.
The nominal diameter of the gaps may be of: 180, 225, 270, 315 or 360 mm.
The minimum distance between gaps is 1/9 of the gaps diameter.
The total height of the BubbleDeck slab elements is constant. Function of the diameter of the bubbles that are used, the total height may be: 230, 280, 340, 390 or 450 mm.
It’s a fact that regardless of the diameter of the bubble used, respectively the thickness of the slab, the own weight stays practically constant.
In order to increase the shear strength capacity and bending moment in the areas with stress concentration (for example near the columns or walls) it is possible that in these areas gaps are not provided.
The surface of the filled (no gaps) areas are chosen function of the loads and the thickness of the slab. The BubbleDeck slab gaps elements can be delivered in the following versions: Version A. Reinforcement modules in which the spheres are placed to produce the gaps and if the case, tubes for HVAC (electrical, heating, etc.), modules that are to be placed in formworks. The plates are cast in place. Version B. Partial precast concrete elements. They have the bottom part made of precast concrete and the connections between elements and the overconcreting are cast in place. In this version the elements are delivered as manufacturing made elements, consisting of a precast concrete layer with 60 mm thickness in which is embedded the bottom part of the reinforcement shell of the entire slab element, the bottom part of the spheres that make the gaps and, function of situation the HVAC tubes. The precast concrete layer from the bottom part is used also as horizontal formwork at the bottom part. The partially precast elements are made with widths of 2,400 mm or 3,000 mm and spans up to 14 m. The concrete used for the precast layer can be of common concrete or selfleveling concrete. Minimum class of concrete is C20/25.
Advantages:-
- Design freedom – flexible layout easily adapts to irregular & curved plan layouts.
- Reduced dead weight -35% removed allowing smaller foundation sizes.
- Longer spans between columns – up to 50% further than traditional structures.
- Downstand beams eliminated – quicker and cheaper erection of walls and services.
- Load bearing walls eliminated – facilitating MMC with lightweight building envelopes.
- Reduced concrete usage – 1 kg recycled plastic replaces 100 kg of concrete.
- Environmentally green and sustainable – reduced energy & carbon emissions.
- 8% of global CO2 emissions are due to cement production. 1 tonne of cement
- Releases 1 tonne of CO2
- Consumes 5 million BTU of energy
- Uses 2 tonnes of raw materials
BubbleDeck concrete
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