Concrete is the material which is formed by mixing cement, sand and aggregates with water in a fixed proportion which get harden after some time.
Use of Concrete in Building Construction:
· Foundation
· Column
· Beam
· Slab etc
In a building there are two types of mix: nominal mix and Design mix
Ratio and proportion of Design Mix.
Design Mix M20:
· Ratio: (1:2.48:3.55)
· Cement: 320 Kg/Cum
· 20mm Jelly: 683 Kg/Cum
· 12.5mm Jelly: 455 Kg/Cum
· River Sand: 794 Kg/Cum
· Total Water: 176 Ltr
· Admixture: 0.7%
· Fresh Concrete Density: 2430 Kg/Cum
Design Mix M25:
· Ratio: (1:2.28:3.27)
· Cement: 340 Kg/Cum
· 20mm Jelly: 667 Kg/Cum
· 12.5mm Jelly: 455 Kg/Cum
· River Sand: 775 Kg/Cum (With 2% Moisture)
· Total Water: 185 Ltr
· Admixture: 0.6% (Micro silica)
· Fresh Concrete Density: 2414 Kg/Cum
Design Mix M30:
· Ratio: (1:2:2.87)
· Cement: 380 Kg/Cum
· 20mm Jelly: 654 Kg/Cum
· 12.5mm Jelly: 436 Kg/Cum
· River Sand: 760 Kg/Cum ( with 2% moisture)
· Total Water: 187 Ltr
· Admixture: 0.7% (Micro silica)
· Fresh Concrete Density: 2420 Kg/Cum
Design Mix M35:
· Ratio: (1:1.79:2.57)
· Cement: 410 Kg/Cum
· 20mm Jelly: 632 Kg/Cum
· 12.5mm Jelly: 421 Kg/Cum
· River Sand: 735 Kg/Cum ( with 2% moisture)
· Total Water: 200 Ltr
· Admixture: 0.7% (Micro silica)
· Fresh Concrete Density: 2400 Kg/Cum
Design Mix M40:
· Ratio: (1:1.67:2.39)
· Cement: 430 Kg/Cum
· 20mm Jelly: 618 Kg/Cum
· 12.5mm Jelly: 4412 Kg/Cum
· River Sand: 718 Kg/Cum (Bulk Age 1%)
· Water Cement Ratio : 0.43
· Admixture: 0.7% (Micro silica)
· Fresh Concrete Density: 2400 Kg/Cum
Note: Design Mix varies as per Code.