What Is A Bubble Deck Slab? Types Of Bubble Deck Slab
What Is A Bubble Deck Slab?
Bubble Deck is a new technology that utilizes hollow or foam-filled plastic balls to replace a large portion of the concrete in a slab. This creates a “voided biaxial slab” with a natural cellular structure that performs similarly to traditional solid reinforced concrete slabs.
However, Bubble Deck has several advantages, such as reducing dead weight by up to 35%, allowing for longer spans and greater design flexibility, and being more environmentally friendly and cost-effective.
Additionally, it can span far longer, without the need for beams, and achieve greater cantilevers and it can be made from recycled materials.
Types Of Bubble Deck Slab
There are three types of bubble deck slabs: Type A, Type B, and Type C.
Type A, known as Filigree Elements, combines precast and unconstructed elements. The concrete layer and part of the finished depth are precast, and the bubbles and steel reinforcement are added on-site. This type is best for new construction projects where the bubble positions and steel mesh layout can be determined.
Type B, known as Reinforcement Modules, is a pre-assembled steel mesh and plastic bubble module that is brought to the site, laid on traditional formwork, connected with additional reinforcement, and concreted in place. This type is best for construction areas with tight spaces since the modules can be stacked for storage.
Type C, known as Finished Planks, is a shop-fabricated module that includes plastic spheres, reinforcement mesh, and concrete in its finished form. The module is delivered on-site as a plank and is best for shorter spans and limited construction schedules, but requires the use of support beams or load-bearing walls.
Material used in Bubble Deck Slab
The materials and specifications used in a bubble deck slab include;
Concrete with a grade of M20-25 or higher for joint filling, with self-compacting concrete being commonly used for casting or joint filling on site.
Reinforcement bars made of steel with a grade of Fe-500 or higher, arranged in two meshes for lateral and vertical support.
Hollow bubbles made of high-density polypropylene, with a non-porous material that does not react chemically with concrete or reinforcement bars.
These bubbles have enough strength and stiffness to support a slab depth of 230mm to 600mm, with a minimum distance between bubbles of 1/9th of their diameter. The nominal diameter of the gaps can be 180, 225, 270, 315 or 360mm, and the bubbles can be spherical or ellipsoidal in shape.
Installation of Bubble Deck Slab
The installation process for a bubble deck slab involves dividing the floor area into individual elements, each up to 3 meters wide, based on site access. These elements consist of top and bottom reinforcement mesh joined together by vertical lattice girders, with void formers trapped between the mesh to fix their position. A layer of 60mm pre-cast concrete is cast to encase the bottom mesh reinforcement and provide formwork for part of the slab’s depth.
On-site, the individual elements are then joined together using loose reinforcement across the joints, and finally, concrete is poured and cured.
This technique creates a seamless, structurally continuous biaxial floor slab by eliminating the structural effect of the joints between elements.
Advantages of Bubble Deck Slab
The advantages of using a bubble deck slab include superior statics, improved production and construction, reduced transportation costs, significant economic savings, increased safety, environmental benefits, and enhanced resistance to explosions.
The bubble deck slab has reduced weight and increased strength, fewer columns, and no beams or ribs under the ceiling. The automated production of prefabricated units results in higher quality construction and less room for errors.
The lightweight of the slab also allows for easier erection with light and cheap lifting equipment. Transportation costs and materials are greatly reduced, resulting in economic savings and environmental improvement.
The bubble deck slab is fireproof and offers increased safety in the event of an earthquake. Additionally, the use of plastic bubbles in the slab reduces energy consumption and emissions of CO2. The biaxial flat slab system and columns of the bubble deck slab also make it ideal for structures with high resistance to explosions.