1. SAB 3122 CONSTRUCTION TECHNOLOGY AND ESTIMATING CONCRETE AND REINFORCEMENT
Dr. Chai Chang Saar

2. CONCRETE WORKS 3 MAIN ITEM concrete reinforcement bar formwork
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3. Concrete Mixing on Site using Cement, Sand & Aggregate
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4. MATERIAL 1) CONCRETE Material
Material from mixture of cement : sand : aggregate & water
Example: 1: 2 : 4 (Concrete Grade 20), 1:3:6 (Concrete Grade 10)
Cement
Aggregate
Sand
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Concrete Mixing on Site using Cement, Sand & Aggregate

5. MATERIAL Shrinkage - Shrinkage when pour up
Wastage - Wastage when placing, mixture
Consolidated -Consolidated when compacted
Consolidation compacts fresh concrete to mold it within the forms and around embedded items and reinforcement and to eliminate stone pockets, honeycomb, and entrapped air.
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Concrete Mixing on Site using Cement, Sand & Aggregate

6. LABOUR
There are 3 types for concrete mixing on site using cement, sand & aggregate:
1) Mixing, hoisting & placing by hand
Average output to mix the concrete 2.00hr/m3 concrete
2) Mixing by plant with hoisting & placing by hand
3) Mixing, hoisting & placing by plant
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Concrete Mixing on Site using Cement, Sand & Aggregate

7. LABOUR Hoisting & placing by hand (Table 1)
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Concrete Mixing on Site using Cement, Sand & Aggregate

8. MIXING, HOISTING & PLACING BY HAND
Build up rate for 1m3 reinforced in-situ concrete Grade 25 ( 1:1½:3) in isolated column by hand.
Assumption
Concrete Grade 25= 1:1½: 3
Cement = RM 13.00/bag (1m3=28 bag)
Sand = RM 16.50/m3
Aggregate= RM 35.00/m3
Mixing =2hr/m3
Hoist and placing = 8hr/m3
General worker =RM40/day
Allow 25% of shrinkage, wastage & consolidated
Allow 20% profit and overhead (Applicable to all build up rate)
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Concrete Mixing on Site using Cement, Sand & Aggregate

9. MIXING BY PLANT, HOISTING & PLACING BY HAND
Machinery/plant
Mixing by concrete mixer (Table 2)
Size of mixer
Workers needed
Output/hr (m3
Diesel/hour (litre)
Lubricator/hour (litre)
5/3½
1 operator
1 general
1.25
1.10
0.04
7/5
3 general
2.25
1.60
0.06
10/7
4 general
3.25
1.80
0.07
14/10
4.50
2.10
0.08
18/12
6 general
5.50
2.40
0.10
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Concrete Mixing on Site using Cement, Sand & Aggregate

10. MIXING BY PLANT, HOISTING & PLACING BY HAND
Build up rate for 1m3 of reinforced in-situ concrete Grade 25 (1:1½:3) in isolated column.
Assumption:
Concrete mixer 7/5
Life-cycle = 4 year
Purchase value = RM 15,000.00
Scrap value = RM 2,000.00
Interest = 10%/year
Maintenance = 10%
Mobilization = 5%
Diesel = RM 1.90/litre
Lubricator = RM 20.00/litre
Average working day = 200day/year
Operator = RM 50.00/day
General Workers = RM 40.00/day
To build up the cost for 1m3 concrete, shall include:
Material cost
Cost of concrete mixer and labours
Cost for hoisting and placing by hand
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Concrete Mixing on Site using Cement, Sand & Aggregate

11. MIXING, HOISTING & PLACING BY PLANT
Build up rate for 1m3 reinforced in-situ concrete Grade 25 (1:1½:3) in isolated beams – m3
Assumption:
Crane 15 tonne (rental) = RM /day (inclusive operator & fuel)
Crane output for placing = 15m3/day
5 general worker for hoisting & placing
Material cost/m3 (as previous) = RM
Mixing cost by mixer/m3 (as previous) = RM
Cost for hoisting & placing by crane
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Concrete Mixing on Site using Cement, Sand & Aggregate

12. Ready Mixed Concrete
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13. READY MIXED CONCRETE Ready mixed concrete
Concrete is ready mixed in the factory and will send to site by supplier
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Ready Mixed Concrete

14. READY MIXED CONCRETE
Build up rate for 1m3 ready mixed reinforced concrete Grade 25 in isolated beams
Assumption:
Rental crane 15 tonne = RM /day (inclusive operator & fuel)
Crane output to placing = 15m3/day
5 general worker to hoist & placing
Ready mix concrete = RM /m3 (inclusive delivery to site)
Allow 5% concrete wastage
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15. Reinforcement
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16. Tying bar for 1 tonne (kg)
RE-BAR MATERIAL
Add 5% wastage for re-bar
Allowance for rebar wire
Table 3
Diameter (mm)
Tying bar for 1 tonne (kg)
6-12 10
16-25 6
32-50 5
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17. RE-BAR LABOUR Output general worker 1.50 hr for 1 tonne bar
Output for cutting, bending (Table 4)
Output for placing (Table 5)
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18. RE-BAR
Build up rate for 1 kg of 16mm diameter High Tensile reinforcement in straight and bent bars in foundation
Assumption:
Cost for 16mm dia = RM 1,800/tonne
Cost for tying bar = RM 3.50/kg
General Workers = RM per day
Cutting, bending & placing = RM per day
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19. FABRIC REINFORCEMENT MATERIAL Allow 5 % wastage
Allow 10% for tying bar
Allow 10% for lapping
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20. FABRIC REINFORCEMENT LABOUR Output for general worker 0.15hr/m2
Output for cutting, bending, placing
Location
Barbender-hr/m2
Bed, floor, roof
0.20
Foundation
0.25
wall
0.33
Staircase
0.50
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21. FABRIC REINFORCEMENT
Build up rate for1m2 fabric reinforcement BRC A6 in suspended floor slab
Assumption
Fabric reinforcement per pcs = RM 70.00
1 pcs of fabric reinforcement = 6.00m x 2.20m
General Workers = RM per day
Cutting, bending & placing = RM per day
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22. Formwork
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23. MATERIAL Can be used more than once:
-Slab and wall can be up to 6 times usage
-Foundation, beam and column normally only for 4 times usage
Nail is inclusive in the built up rate, 0.35kg/m2
10% of formwork wastage
Strutting for formwork
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24. STRUTTING Strutting Location Strutting (m3) Side of column 0.02
Sides of fdnt & wall
0.04
Sides & soffit of beam
0.05
Sides & soffit of slab
0.06
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25. LABOUR Determine sawn formwork or wrought/wrot formwork
Add 25% for wrought formwork
Output to prepare, placing and take out
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26. FORMWORK
Build up rate for 1m2 Sawn formwork to soffit of suspended floor slab.
Assumption:
12mm thick board with 2.40m x 1.20m = RM 35.00/piece
Timber = RM 900/tonne (1 tonne = 1.40m3)
Nail = RM 4.50/kg
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27. THE END
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