How can I calculate the amount of concrete required for a slab ?

it is differes from solid slab to flat slab to hollow block salb which one do you mean?

you should know dimensions of slab &thickness multiply L*w*t or get the area from autocad multiply it by depth .
don't forget to deduct the opening area

There are ways to calculate concrete volume.

1. Dry Material Qty

2. Solid Qty

 

For Example

1.  Dry Material Qty of Concrete

 

RCC Concrete (1:2:4)  

1 Cement Vol   =0.035 CM

 

Wet Volume of Concrete =135CM

Dry Volume of Concrete=135x1.54 =207.90 CM

Rate of Concrete =1:2:4

Sum of Ratio:1+2+4 =7

Quantity of steel =1% of wet Quantity of concrete

 

=1/100 x135 =1.35CM

=1.35 x7850 =10597.5 Kg =105.975 qintal

 

Quantity of Cement            =1/7x207.90           = 29.69 CM

                                           =29.69/0.035        =846.28 Cement Bags      

 

Quantity of Sand                =2/7x207.9            = 59.40 CM

 

Quantity of Gravel/Crush  =4/7x207.9            =118.8 CM

 

Sum of Ratio Qty=29.69+59.4+118.8 = 207.9 CM 

 

 Example no .2

Solid Qty of Concrete

Roof Slab Covered Area (30M x22 M)

Formula= Length x Width x Depth/ Height   

             =30 x22 x0.15 =99 CM

 

 

JUST TAKE THE DIMENSINS OF THE SLAB AND CALCULATE THE VOLUME.MULTIPLY BY A FACTOR1.52 THIS WOULD BE THE QUANTITY OF CONCRETE

To calculate the cost of concrete required for slab shall be done by following steps Total Cost = Labour Cost + Material Cost + Plant Cost a) Labour Cost shall be calculated based on the no.
of different categorized manpower required to perform a job and their daily wages.
(eg.
mason, Helper, Rigger, Pipe Fitter etc.,) b) Material = Construction Material Cost + Shuttering Material Cost Cost of Cement, aggregates, rebar, embedments, pipe conduits will come under the construction material cost.
Quantity of cement, aggregates, admixture shall be calculated based on the concrete mixed design of the Concrete Grade.
Cost of Plywood, steel shutter, formwork materials will be considered the depreciation cost as these materials having repeatation of work and thus will come under the shuttering material cost c) Plant Cost = Hire charges of Equipments like Builder Hoist, Concrete pump boom placer, vibrator, transit mixer, batching plant.