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Different Types of Slabs Used in Construction and Their Uses, Advantages & Disadvantages

What is a Slab?
Slabs create flat, usually horizontal surfaces in building floors, roofs, bridges, and other constructions. Walls can support the slab, and reinforced concrete beams are normally cast monolithically with the slab, structural steel beams, columns, or the earth itself.

Different Types of Slabs Used in Construction:
1. Flat Slab:
Fig 1 Flat Slab
Fig 1: Flat Slab
Courtesy: civildigital.com


The flat slab is a reinforced concrete slab supported by concrete columns or caps. The flat plate is also beamless since it has no columns. Loads are delivered directly to pillars. This type of structure gives the structure an appealing artistic appearance. The simple roof disperses heat more quickly than a standard column plate structure and is considered less flammable in the case of a fire. The plain plate is easier to construct and requires less contouring. The Flat slab must be at least 8 inches thick (200mm).

Uses of Flat Slab:

Advantages of Flat Slab:

Disadvantages of Flat Slab:

2. Hollow-Core Slab:
Fig 2 Hollow –Core Slab
Fig 2: Hollow –Core Slab
Courtesy: kipahprecast.com

It’s a form of the precast slab with cores running through it. These cores reduce slab self-weight and improve structural efficiency, serving as service ducts. It’s ideal for situations where the quick building is required. The span of the hollow core slab units is unrestricted, and their normal width is 120mm, with depths ranging from 110mm to 400mm.

Cranes are typically used to place slab units between beams, and the gaps between units are filled with screeds. Over a 16-meter span, a hollow core slab has been found to hold 2.5 kN/m2. It’s ideal for office, retail, and parking-lot buildings.

Uses of Hollow-Core Slab:
Using a hollow-core ribbed slab decreases construction expenses and the structure’s overall weight. Because of its thickness, a hollow core slab provides excellent fire resistance and sound insulation. It removes the requirement for electrical and plumbing units to be drilled into slabs.

Advantages of Hollow-Core Slab:

Disadvantages of Hollow-Core Slab:

3. Conventional Slab:-
Fig 3 Conventional Slab3
Fig 3: Conventional Slab
Courtesy: pole-arn.infot.com

A standard plate is a plate that is endorsed on beams and pillars. In this kind, the slab thickness is small, but the beam depth is great, and the weight is transferred to beams and columns afterward. It requires more formwork than the simple plate, and there is no need to offer traditional plate-style panel caps.
The standard slab thickness is 4?? (10 cm). 5?? to 6?? inches is recommended if the wood is subjected to frequent high loads, such as engine trucks or rubbish carts. These slabs are divided into two categories based on their length and width: – i) One-way Slabs and ii) Two-way Slab.

i) One-way Slab:
A one-way flat slab, one of the most prevalent slab types in construction projects, a one-way flat slab uses 4 to 6 inches of concrete to sustain large loads. The slab’s name refers to the support structure. It’s used when one direction is supported while the other requires less support.
This slab is a cost-effective and straightforward option for commercial or residential construction. It’s less expensive than other slab kinds, especially for a ground-level structure. One of the biggest drawbacks of one-way flat slabs is that they can’t span as much as other slab kinds. As a result, they are inappropriate for various bridge and ceiling applications.

ii)Two-way Slab:
It is known as a two-way slab because beams support it on all four sides, and the supports carry the weights in both directions. The ratio of longer span to shorter span in a two-way slab is less than two due to the likelihood of the slabs bending to the four supporting edges in both directions.
This type of slab has a length and width of more than 4 meters of length and width. In a two-way slab, distribution bars are installed at both ends to prevent the buildup of strains. These slabs are utilized in the construction of multi-story buildings floors.

4. Waffle Slab:
Fig 4 Waffle Slab
Fig 4: Waffle Slab
Courtesy: prodyogi.com

This type of slab has a length and width of more than 4 meters of length and width. In a two-way slab, distribution bars are installed at both ends to prevent the buildup of strains. These slabs are utilized in the construction of multi-story buildings floors.

Uses of Waffle Slab:
A waffle slab is a slab with holes underneath that resembles waffles. When vast spans are necessary (e.g., auditoriums, cinema halls), it is typically employed to eliminate many columns interfering with space. As a result, thick slabs spanning between wide beams are required (to avoid the beams intruding below for aesthetic reasons). The main reason for using this technique is its great foundation crack and sagging resistance. In comparison to normal concrete slabs, waffle slabs can hold more weight.

Advantages of Waffle Slab:

Disadvantages of Waffle Slab:

5. Hardy Slab:
Fig 5 Hardy Slab
Fig 5: Hardy Slab
Courtesy: theconstructor.org

A hardy slab is a concrete slab made out of full bricks. Hardy bricks are made up of hollow concrete blocks and are hollow bricks. This type of block is used to fill in gaps in the slab. Hardy slabs lower the quantity of concrete in the slab while also reducing the slab’s weight. Compared to traditional slabs, this one has a thickness of 2.27 m.

Uses of Hardy Slab:
Where temperatures are high, a hardy slab is used. The thickness of the slab is increased to resist the heat from the top. The heat from the walls is resisted by utilizing thermal-infused unique bricks. Thermal is the best sunlight insulator.

Advantages of Hardy Slab:

Disadvantages of Hardy Slab:

6. Dome Slab:
Fig 6 Dome Slab
Fig 6: Dome Slab
Courtesy: largoconcrete.com

A dome slab can be used to build a distinctive mosque, temple, or palace dome. A steel support structure is used to sustain this semi-circle concrete structure, and The concrete is reasonably thick. It is meticulously poured into a smooth or textured dome shape utilizing a framework.

Uses of Dome Slab:
One of the key advantages of the dome-shaped system is its capacity to deliver structural carrying capacities comparable to traditional slabs while using less concrete.

Advantages of Dome Slab:

Disadvantages of Dome Slab:

7. Arch Slab:
Fig 7 Arch Slab
Fig 7: Arch Slab
Courtesy: grabcad.com

It is a form of slab that is frequently used in bridge construction. Bridges are vulnerable to two loads: movement loads and wind loads. Slabs with arches, also known as arch slabs, are used in places where wind loads must be directed and a lengthy curve in the slab’s direction. It prevents the bridge from collapsing due to high winds.

Uses of Arch Slab:
An arch is a curving piece used to span an opening and support loads from above in architecture and civil engineering. The vault’s development was built on the foundation of the arch.

Advantages of Arch Slab:

Disadvantages of Arch Slab:

8. Pitch Roof Slab:
Fig 8 Pitch Roof Slab
Fig 8: Pitch Roof Slab
Courtesy: civiljungle.com

The pitching slab’s roof is a sloping slab commonly used in resorts for a natural aesthetic. The tiles used in pitch roof slabs are particularly gentle compared to traditional roofing materials. Because of the weight savings, the structural requirements for wood or metal are reduced, resulting in significant cost savings.
Tile sheets are custom-made for each project, saving money on labor and reducing waste on the job site, while the thickness of the slab is determined by the tiles used for 2- 8 inch concrete slabs.

Uses of Pitch Roof Slab:
Pitched roofs allow for natural airflow between the outer layer and the structure, saving energy.

Advantages of Pitch Roof Slab:

Disadvantages of Pitch Roof Slab:

9. Post Tension Slab:
Fig 9 Post Tension Slab
Fig 9: Post Tension Slab
Courtesy: aftconstruction.com

The slab in tension after it has been formed is known as a post-tension slab, and it is reinforced to withstand compression. The post-stress slab’s reinforcement is replaced with cables/metal tendons. Post-tensioning allows you to overcome concrete’s inherent weakness under stress and better exploit its strength in compression.

Uses of Post tension Slab:

Standard reinforcing steel (rebars) provides various advantages over post-tensioning, which is a type of prestressing: It decreases or eliminates shrinkage cracking, necessitating the use of no or fewer joints. When cracks do appear, they are held together strongly. It allows for thinner slabs and other structural elements.

Advantages of Post Tension Slab:

Disadvantages of Post Tension Slab:

10. Pre Tension Slab:
Fig 10 Pre Tension Slab
Fig 10: Pre Tension Slab
Courtesy: macchiagroup.net.au

The pre-tension slab is tensioned before being inserted, and it has certain characteristics of a post-tensioning slab.

Uses of Pre Tension Slab:
Pre–tensioning is often done on permanent beds at precasting factories that produce pre-tensioned precast concrete elements for the construction sector.

Advantages of Pre Tension Slab:
Longer span lengths provide more open floor area and parking. Longer spans mean fewer joints, which means less maintenance is required. Because concrete is crack-free, the possibility of steel corrosion and subsequent concrete deterioration is reduced.

Disadvantages of Pre Tension Slab:

11. Low Roof Slab:
A low roof slab refers to the slab above the door for storage purposes. This slab has closed ends on all sides and an open end on one side. This slab is above the door sill level and below the real slab. These are the varieties of concrete slabs that are seen in homes.

Advantages of Low Roof Slab:

Disadvantages of Low Roof Slab:
Low-slope roofs alter the way water drains from a building. Because high-pitched roofs don’t allow water to collect, asphalt shingles and other overlapping materials perform effectively. Standing water soaks between these materials on a roof with a lower pitch.

12. Cable Suspension Slab:
Fig 11 Cable Suspension Slab
Fig 11: Cable Suspension Slab
Courtesy: midasbridge.com

If the slab span is particularly long, we use a cable suspension slab supported by cables like London Bridge and Howrah Station. We supply a column every four meters; however, we provide a column every 500 meters in a cable suspension slab. This slab is used when the span is longer, and the formation of columns is difficult. A cable holds the slab and connects it to the cable column.

Uses of Cable Suspension Slab:
Where the span length is longer and more challenging in building columns, this type of slab is given. Cables connect the slabs to the columns.

Advantages of Cable Suspension Slab:

Disadvantages of Cable Suspension Slab:

13. Projected Slab:
Fig 12 Projected Slab
Fig 12: Projected Slab
Courtesy: iceted.com

A projected slab is generally included in a covered drop-off entrance. At one end, this long slab is attached to a building, while at the other, it swings freely. The purpose is to keep automobiles and pedestrians safe from the sun and bad weather. The slab employs a cantilever design to balance the weight and sustain it safely from a single end.

Uses of Projected Slab:
These slabs are commonly found in hotels, universities, and event halls and are used as a drop-off and pick-up zone and a loading and unloading zone.

Advantages of Projected Slab:

14. Ground Slab:
Fig 13 Ground Slab
Fig 13: Ground Slab
Courtesy: 123rf.com

The slabs poured directly into excavated trenches in the ground are known as ground slabs. They are completely reliant on the existing terrain for support. A sturdy foundation must support the concrete slab.

Uses of Ground Slab:
Ground-bearing slabs, also known as “on-ground” or “slab-on-grade” slabs, are often used for ground floors in residential and commercial buildings. It is a cost-effective and time-saving construction approach for locations with non-reactive soil and a low slope.

Advantages of Ground Slab:

Disadvantages of Ground Slab:
There are several advantages to building or purchasing a home on a slab, including financial savings and a reduced danger of damage in certain situations. The disadvantages include the possibility of having to install heating and cooling systems on the ground floor, which eats up living space. There’s also the possibility of cracks.

15. Sunken Slab:
Fig 14 Ground Slab
Fig 14: Ground Slab
Courtesy: constrofacilitator.com

A sunken slab is utilized below the washrooms to cover sewer pipes, WC pipes, and other equipment. Because the water pipes are hidden beneath the earth, care must be taken to avoid leaks.

For leakage or moisture, the slab is properly waterproofed and treated. Following the installation of the sewer lines, the slab is filled with broken bricks, coal, or other suitable lightweight material.

Uses of Sunken Slab:
Bathrooms, toilets, washing machines, and water closets all use this slab style. The objective of a sunk slab is to prevent water from spilling over into the surrounding slabs from the sunk slab.

Advantages of Sunken Slab:
All plumbing pipes are concealed within the slab with such slabs.
Special plumbing fixtures in sunken strips are not required for noise in the bathroom.
These slabs provide a good plumbing system and can also be utilized to create a safety system.

Disadvantages of Sunken Slab:

Conclusion:
The various types of slabs in a typical structural system prevent transverse forces on their plane, allowing for higher structural efficiency.

References:
1. LCETED. (2001, April 3). Different types of slabs in construction | Its uses | Pros & Cons -lceted LCETED INSTITUTE FOR CIVIL ENGINEERS. LCETED INSTITUTE FOR CIVIL ENGINEERS; www.lceted.com. https://www.lceted.com/2021/04/different-types-slabs-in-construction.html
2. mohdsuhel. (2021, February 5). Types of Slabs in Construction. CivilMint.Com; civilmint.com. https://civilmint.com/types-slabs-construction/
3.What is Slab? Types of Slabs- civilengineer-online.com. (2019, September 13). Civilengineer-Online.Com; civilengineer-online.com. https://civilengineer-online.com/what-is-slab-types-of-slabs/
4. 16 Different types of slabs in construction | Where to use? (2017, May 21). CIVIL READ; civilread.com. https://civilread.com/16-different-types-slabs-construction/
5. Rajput, K. (2021, April 5). 19 Different Types of Slabs in Construction | What Is a Slab. CivilJungle; civiljungle.com. https://civiljungle.com/types-of-slabs/
6. 7. Types of Slabs in Construction (20 Different Types). (2021, February 24). Constructionor.Com; constructionor.com. https://constructionor.com/types-of-slabs/

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Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

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