Some Important Codal Provisions To Be Remembered

• Lapping is not allowed for the bars having diameters more than 36 mm.
• For dowels rod minimum of 12 mm diameter should be used.
• Longitudinal reinforcement of RCC column not less than 0.8% and more than 6% of gross C/S.
• Minimum bars for a square column is 4 No’s and 6 No’s for a circular column.
• The main bars in the slabs shall not be less than 8 mm (HYSD) or 10 mm (Plain bars) and the distributors not less than 8 mm and not more than 1/8 of slab thickness.
• The minimum thickness of slab is 125 mm.
• Dimension tolerance for cubes + 2 mm.
• The freefall of concrete is allowed a maximum of 1.50m.
• Water absorption of bricks should not be more than 15 %.
• pH value of the water should not be less than 6.
• The compressive strength of Bricks is 3.5 N / mm2.
• In steel reinforcement binding wire required is 8 kg per MT.
• In soil filling as per IS code, 3 samples should be taken for core cutting test for every 100m2.

Density of Materials

Material	Density
Bricks	1600 – 1920 kg/m3
Concrete block	1920 kg/ m3
Reinforced concrete	2310 – 2700 kg/ m3

Curing time of RCC Members for different types of cement

Super Sulphate cement: 7 days

Ordinary Portland cement OPC: 10 days

Minerals & Admixture added cement: 14 days

De-Shuttering time of different RCC Members

RCC Member	De-shuttering time
For columns, walls, the vertical formworks	16-24 hrs.
Soffit formwork to slabs	3 days (props to be refixed after removal)
Soffit to beams props	7 days (props to refixed after removal)
Beams spanning up to 4.5m	7 days
Beams spanning over 4.5m	14 days
Arches spanning up to 6m	14 days
Arches spanning over 6m	21 days

Cube samples required for different quantity of concrete

Quantity of Concrete	No. of cubes required
1 – 5 m3	1 No’s
6 0 15 m3	2 No’s
16 – 30 m3	3 No’s
31 – 50 m3	4 No’s
Above 50 m3	4 + 1 No’s of the addition of each 50 m3