Construction Process of RCC Slab in Building

Construction process of the RCC slab

 Construction process of RCC Slab Video

What is the slab?

A concrete slab is a common structural element of modern building, consisting of a flat, horizontal surface made of cast Concrete

Many different types of slabs are there like a 

• flat slab
• conventional slab
• cantilever slab
• graded slab
• sunken slabs etc

 we will discuss Commonly used Conventional slab as below

Step 1 Assemble and erection of formwork

I. Stagging work

That portion which supports centering and Shuttering is called stagging.

Stagging work is done based on site conditions and type of material is available on site

• Wooden ballies, bracing,chavi etc
• MS props
• Acrow span 
• H-frames
• Cup lock system, etc

Fig. Shows MS Props used in Slab Shuttering

 Fig. Shows Acrow span used in slab

Fig. Shows Wooden Ballies are used in Slab Stagging work

•  Formwork bracing, wooden pattti, chavi, ply boards of 12mm shall be fixed using nails
•  This formwork shall be designed to withstand construction loads such as fresh concrete pressure, weight of workers and operators and machines
• Formwork must be rigid 
•  shuttering should be positioned correctly as per drawing beam size width and depth and Thickness of the slab 
• Site engineer must check the line and  level of the Shuttering property before start the reinforcement work

Photo shows Shuttering work with the Cuplock system stagging

• Masking tape(3") is applied on the joints of shuttering to minimize leakage of slurry during concrete
• Application of shuttering oil prevents sticking of formwork to the concrete surface thereby permitting easy stripping of formwork after the concrete has hardened.
•  this shuttering process done under the observation of site engineer and after checking start reinforcement work of slab

Photo shows 3" masking tape and oil work on shuttering

Step 2 Preparation and placement of reinforcement bars 

• At the time of designing of the slab, it is considered that concrete strong in compressive strength and weak in tensile strength 
•  prior to the placement of reinforcement for concrete floor slab construction, inspection, and checking of forms to confirm that the dimensions and the location of the concrete members. Confirm to the structural plans
•  forms shall be properly cleaned and oiled. Oil, not such amount as to run onto bars

I. Bending and binding of steel bars 

•  design drawings provide necessary reinforcement details, so it only needs understanding to use designed bar size, cutting length and necessary hooks and bents
•  steel bars required for beams and slabs get it done as per structural drawings

Photo shows steel cutting and bending work in steel yard

II. Positioning of steel bars

•  after preparation is completed, steel bars are placed into their positions with the provision of specified spacings and concrete cover
•  Concrete cover and spacing maintained by introducing spacers and Chairs in th slabs 
•  Bending wires are used to tie the reinforcement bars in position 
•  this reinforcement is checked by site engineer as per general drawings and structural drawings

Photo shows steel placing work is in progress

3. Electrical and Plumbing points/cutouts

•  after completing the reinforcement work, we start the electrical conduits works
• Concealed Conduit Electrical Wiring systems are the most popular, aesthetically appealing, and most common type of House Electrical wiring used. 
• Conduit wiring is a professional way of wiring a building. Mostly PVC conduits are used in domestic wiring.
•  plumbing pipes and cutouts are provided for pipeline work in building 
•  this Electrical and Plumbing points or cutouts shall be checked by respective MEP engineers before Starting of Concrete

Photo shows Electrical conducting work and plumbing sleeves provided in slab

Step 4 Pouring and finishing work of Concrete 

• Slab casting should be done in Systematic manner, 
•  how to place the concrete is  planned as per the slab and available concrete transportation ways 
• walkway ghodas are provided for walking on the slab to avoid disturbance in steel bars 
•  Make Concrete as per design grade on-site or arrange the RMC concrete for concrete as per availability
• transportation of concrete is s done by dumpers, wheelbarrow or tower crane bucket or Concrete Pumps 
• Slab thickness Control Gauges are provided to maintain the thickness of the slab
• Concrete begin concrete placing along the perimeter at one end of the work with each batch placed against previously poured or dispatched concrete
• this concrete vibrate with needles until bubbles stop rising to surface 
• this fresh concrete should be compacted adequately
• slab should be roughly floated with a trowel or hand floats to give smooth surface to the concrete top
• Carry out the light brooming on the slab top before curing

Photo shows pouring of concrete from one end stated

5. Curing of Concrete and Removal of formwork

•  after finishing ended, as soon as the concrete is dry enough and no thumb impression is observed Concrete curing should be started as per time period
• water cure, concrete is flooded, ponding on slab curing is done 
• generally, making watta, using cement sand mortar and fill water 
• after achieving strength14 or 28 days as per requirement, formwork is removed

Photo shows finished concrete surface with light Brooming work 

Watch full video on YouTube below link 

https://youtu.be/DFQsrek28MI