A concrete slab is a horizontal, two-dimensional rigid structural component used widely in domestic and commercial buildings. It is largely composed of cement along with a certain amount of sand, water and aggregates. The usage of various slabs is pertinent to the building as it assists in getting the desired structure.
Advantages of Concrete Slabs
Concrete slabs provide several structural and functional benefits to a building.
As a concrete slab is a rigid, long-lasting structure so its prime advantage is to add durability to a structure. Using a concrete slab offers durability and enhances the lifespan of any building.
Greater Compressive Strength
As a concrete slab consists of sand and rock aggregates, it has a greater capacity to withstand bulky weights. Thus, using concrete slabs in high-rise and massive structures is recommended.
Another significant feature of concrete slabs is their ability to regulate temperature variations within a building. The slabs have a high thermal mass which means they have a remarkable ability to absorb and radiate heat. Hence, concrete slabs help to maintain a suitable temperature in the ambient environment.
Shorter Drying Time
Concrete slabs have less drying time, so they assist in carrying out construction swiftly. You do not have to wait for many days to dry them. Hence, you can move on with the project without any delay.
Minimum Risk of Damage
Concrete slabs have a high resistive ability and provide a strong base that’s why using concrete slabs lowers the risk of damage from flooding or humidity.
Safety from Pests
The usage of concrete slabs in the house hinders the prevalence of pests. As there are no open spaces in concrete slabs, insects do not find any space to consume wooden structures and thrive. For additional safety, we can also pre-treat slabs with insecticides to limit insects’ growth.
Other than offering many advantages, concrete slabs prove to be an economical solution. When you use these slabs in the base of your house, then the high additional cost of any crawl space or basement can be saved, which means thousands of dollars. The idea of using concrete slabs also remains effective when someone has to give a strong base to one’s home.
Want to know uses of Concrete Consider Reading: Multiple Uses of Concrete
Types of Concrete Slabs
There are many types of concrete slabs, and each one is suitable to fulfil a certain requirement. Let’s explore some of the commonly used types.
Conventional slabs are generally supported on beams, columns or walls. It requires more ingredients than flat slabs to construct a conventional slab, yet they don’t need column caps as it is in the case of flat slabs. These slabs transfer the load to supporting walls and beams. Conventional slabs have further two types:
One Way Slabs
Such slabs are supported on the beam from two opposite sides and distribute the load in one direction only.
Two Way Slabs
A two-way slab relies on beam support from all sides. In two-way slabs, the load distributes evenly in two directions.
A flat slab or a beamless slab is a concrete structure that relies directly on the columns and all the load transfers on them. These slabs are used when someone needs a plain ceiling for better diffusion of light. These slabs also remain effective when there is some height restriction. Commonly such slabs can be seen in parking, hotels or other commercial buildings.
Hollow Core Slabs
As indicated by their name, these slabs have structural voids in them and look like elongated tubes. These are lighter in weight and provide greater structural efficiency. Hollow core slabs require less concrete for construction and act as service ducts.
Waffle slabs or grid slabs are conveniently used in hotels, restaurants and shopping malls to give a dandier look. Waffle slabs have grids that can be square, rectangle or triangle. These slabs are lightweight, save a great amount of concrete and support more load as compared to conventional slabs. Thus, waffle slabs can be used for a longer span.
Sunken slabs are laid below the bathrooms but above the sewerage pipes and other sanitary fittings to hide them in a bathroom. As these slabs are adjacent to water pipes, so extra care is needed to avoid leakage issues so that any moisture or dampness does not reach these slabs.
Slab with Arches
These slabs are the best match for constructing a bridge. They have arches in them and can significantly withstand wind pressure by redirecting the wind’s load. Hence, slabs with arches give remarkable support to a bridge from wind thrust or floodwater force.
Cable Suspended Slabs
When it comes to long spans and big structures and where it is difficult or impossible to construct multiple columns, cable-suspended slabs seem to be the best option. These slabs are suspended with the help of cables and need fewer columns to rely on. Usually, this type of slab is used for the construction of bridges.
Bubble Deck Slabs
Bubble deck slabs are constructed using HPDE or high-density polyethene recycled plastic balls. Primarily, the balls are placed, and later on, reinforcement is added followed by fresh concrete to form the bubble deck slabs. These slabs are effective for longer spans and significantly reduce the total volume of concrete.
Additionally, there is no need for a beam and fewer columns are used. So, the total cost of concrete decreases by up to 60%. As these slabs require a comparatively small amount of concrete and have recycled plastic balls, these slabs are environmentally friendly as well.
These are special slabs that are constructed by using hardy bricks joined uniformly. Hardy bricks are hollow with a minimum depth of 200 mm; thus, the total depth of the slab is 200mm. For the construction of hardy slabs, hardy bricks are placed in a row, and the spaces among them are used as beams. Later on, reinforcement and concrete are added to give a final shape.
These slabs are preferably used in areas with high temperatures. These slabs have a greater thickness to minimize the temperature from the top of the slab. Furthermore, special bricks having thermocol are used to resist heat from the walls.
A composite is any material that consists of one or more materials. The composite slabs are constructed of steel decking and concrete in which trapezoidal or rectangular steel decking is used as formwork. Afterwards, these steel formworks are concreted to form composite slabs. These slabs have considerable strength against torsion and deflection. Moreover, they are lightweight, assistive for longer spans, and economical to construct.
Slabs on Grade
Slabs on grade or grade slabs are constructed on the ground having the support of soil. Slab on grade demands firm support, meaning the soil below it should be stiff, levelled, and moisture-free. The minimum depth of the grade slab is 100mm increasing towards the edges to give more to enhance the strength of the slab. It has further 3 types:
Slab on Ground
It comprises a simple concrete slab supported on the beams and has a thickness of 100mm.
Stiffened Raft Slab
This slab is similar to the slab on ground, but it has a framework of beams adjusted in the middle of the slab.
Waffle Raft Slab
This slab lies completely above the ground and is constructed by concreting polystyrene blocks called voids. Comparatively, it uses up to 30% less concrete.
Cantilever Slabs or Projected Slabs
More commonly used in balconies, cantilever slabs are supported on one side only whereas the other side remains free and elongates outwards. Due to this condition, the deflection in these slabs is greater than the others.
The main reinforcement is given in the whole span protruding outside while the secondary reinforcements span over its entire length. As it does not require any support so it’s easier to construct a cantilever slab. However, its disadvantages include high costs and greater deflection that one must consider.
Why It’s Critical to Opt for The Right Type of Slab?
As described above, concrete slabs have so many types, and their key advantages for a building are very evident. Moreover, concrete slabs have certain roles in making a structure quite useful for the inhabitants. Below are some reasons that outline why it’s mandatory to choose the right type of slab for your construction project.
- Slabs are the key elements that remarkably affect the structure of a building. They join beams, columns and walls and help stabilize the building. So proper structure maintenance needs the right slab.
- Choosing the type of slab directly depends on the type of building you are constructing. Whether you have to build a home, a commercial office, a monument, or a bride, the type of appropriate slab will vary. So, always select a slab that suits your structure.
- Do not forget the cost of the slab. As ultimately, you need a structure that is cost-effective yet serves all the benefits. So, choose a slab that is economical, durable and fits in.