The filler slab is a slab construction technology, in which by filler material part of concrete in the bottom of the slab is replaced, and as compared to reinforced cement concrete slabs it consumes less concrete and steel.
Filler slab is based on the concrete portions and instead of placing filler material there and is one cost-effective roofing system. Due to the use of low-cost, less-heavy filler material such as clay pots, rejected Cali-cut tiles, and broken pieces of cement blocks, the filler slab consumes less concrete and steel as compared to conventional RCC slab.
The filler slab is based on the principle that for roofs which are simply supported as the lower part of the slab experience tensile forces while the upper part of the slab is subjected to compressive forces and material used as a replacement includes bricks, cellular concrete blocks, and tiles.
Due to tensile force steel bears the load and concrete are very good in withstanding compressive forces thus except for holding the steel reinforcements together, the lower tensile region of the slab does not need any concrete.
There are many advantages of filler slab like the introduction of a less heavy, low-cost filler material it consumes less concrete and steel and reduced weight of the slab. Due to heat-resistant qualities of filler materials and the gap between two burnt clay tiles it enhances thermal comfort inside the building. It reduces the use of concrete and about 40% saves cement and steel.
Materials for Filler Slab:
There are the following materials for filler slab as given below;
In the grids of steel reinforcement rods these materials are laid and over them concreting or concrete topping is done.
Material Selection as Per Design & Need:
There are the following points to be kept in mind material selection for filler slab;
With concrete or steel in RCC slab constructed the filler material should not react and in nature, it should be inert.
As it will soak the hydration water from concrete so filler materials water absorption should be checked.
In weight filler material should be light so the dead load onto the foundations is reduced and the overall weight of the slab reduces.
The cost of filler material is much lesser then the cost of the concrete it replaces so filler material should be of low cost.
As not to provide an ugly ceiling pattern filler material texture should match with the desired ceiling finish requirements.
Benefits of Filler Slab:
There are the following benefits of filler slab such as;
By different institutions and laboratories, conventional tests have proved the load-bearing capacity of filler slab and found it no less in performance. It does not collapse under the impact like a coconut falling on the roof since filler roof tiles are firmly bonded and covered by concrete.
Leaks can be avoided with proper supervision and workmanship, and the same as the conventional RCC slab the chance of a leak in a filler slab is much.
Saving on Cost:
From 15 percent to 25 percent the savings on cost can be done and to determine the spacing between the reinforcement bars, designing a filler slab requires a structural engineer.
It gives an excellent thermal insulation layer due to the air pocket formed by the contours of the tiles and taking into account the negative zones and reinforcement areas, the design integrity of a filler slab involves careful planning for such slab.
The filler material is left open without plastering to form aesthetic design symmetry in most houses and provide aesthetically pleasing patterned ceilings but some residents prefer to cover the space with plaster of Paris coating which also gives good and pleasing ceilings.