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Slump IS 456

Lightly reinforced 25 – 75 mm
Heavily reinforced 75 – 100 mm
Trench fill (insitu & Tremie) 100 – 150 mm
(For Termie vibrator not required )

Accuracy of measuring equipment in batching plant.

Cement : + 2%
Aggregate : + 3%
Admixture : + 3%
Water : + 3%
Mixing time : 2 minutes for one mixing.(site Mixing)

TOLERANCE :-

Form work:-
In C/S for columns & Beams deviation is = + 12mm more (or) – 6mm less in size
In footing plan = + 50 mm more (or) – 12 mm less size
In depth = + 0.05 D (specified thickness).

Reinforcement:-

For effective depth D < 200mm = + 10mm

For effective depth D > 200mm = + 15mm

For Cover to reinforcement = + 10mm

TOLERANCE ON DIA IN LENGTH:-

0-25mm = + 0.5 %
25-35mm = + 0.6 %
35-50mm = + 0.8 %

TOLERANCE ON WEIGHT PER METRE:-

0-10mm = +7%
10-16mm = + 5%
16 and above = + 3%

TOLERANCE FOR CUTTING LENGTH :-

A) When the specified length is not given = + 75mm (or) – 25 mm
B) When the min. length is specified = + 50 mm (or) – 0 mm

DENSITY OF MATERIALS:-

Weight of Bricks = 1600-1920 Kg/M3
Weight of Block work = 1920 Kg/M3
Weight of R.C.C = 2310 – 2700 Kg/M3

CURING :-

Super Sulphate cement : 7 days
Ordinary Portland cement OPC : 10 days
Minerals & Admixture added cement: 14 days

STRIPPING TIME ( De-Shuttering) :-

For columns, walls, vertical form works : 16-24 hrs
Soffit formwork to slabs : 3 days (props to be refixed after removal)
Soffit to beams props : 7 days props to refix after removal.
Spanning up to 4.50m : 7 days
Spanning over 4.50m : 14 days
Arches spanning up to 6m : 14 days
Arches spanning over 6m : 21 days

CUBE SAMPLES :-

1 – 5 M3 : 1 No.
6 – 15 M3 : 2 No’s
16 – 30 M3: 3 No’s
31 – 50 M3: 4 No’s
Above 50 M3: 4 + 1 No of addition sample for each 50 M3

COMPRESSIVE STRENGTH:-

3 days : 45 %
7 days : 67 – 70 %
14 days : 85 %
28 days : 100% +

WATER CEMENT RATIO:-

M20 = 0.55
M25 = 0.50
M30 = 0.45
M35 = 0.45
M40 = 0.40

SPACING OF BARS :-

 Provide the dia of the bar, if the dia of the bar are equal.
 Provide the dia of the larger bar, if the dia are unequal.
 5mm more than the nominal maximum size of the coarse aggregate.

COVER TO MAIN REINFORCEMENT :-

Column : 40 mm (D>12mm)
Column : 25 mm (D= 12mm)
Beam : 25 mm
Slab : 15 mm (or) not less than dia of the bar.
Footing : 50 mm
Sunshade (Chajja) : 25 mm

STEEL :-

 Weight of rod per meter length = d2/ 162 where d in mm
 “L” for column main rod in footing is minimum of 300mm
 Hook for stirrups is 9D for one side
 For Cantilever anchorage length for main steel is 69D
 No. of stirrups = (clear span/Spanning) + 1
 Design strength is M 40, target strength is 1.25 x 40 = 50 Mpa

THEROTICAL WEIGHT:-

Cement = 1440 Kg/m3
Steel = 7850 Kg/m3
Bricks = 1600 – 1920 Kg/m3
1 HP = 745.7 watts

WEIGHT OF ROD PER METER LENGTH:-

DIA WEIGHT PER METER
6mm = 0.222
8mm = 0.395
10mm = 0.616
12mm = 0.888
16mm = 1.578
20mm = 2.466
25mm = 3.853
32mm = 6.313
40mm = 9.865

CMENT REQUIREMENTS :-

M10 : 210 Kg
M20 : 320 Kg
M25 : 340 Kg
M30 : 380 Kg
M35 : 410 Kg
M40 : 430 Kg
M45 : 450 Kg
M50 : 450 + M.S 7.5%