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

CONCRETE WORKS 3 MAIN ITEM concrete reinforcement bar formwork 11/23/2018

Concrete Mixing on Site using Cement, Sand & Aggregate 11/23/2018

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 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

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. 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

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 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

LABOUR Hoisting & placing by hand (Table 1) 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

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) 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

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 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

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 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

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 400.00/day (inclusive operator & fuel) Crane output for placing = 15m3/day 5 general worker for hoisting & placing Material cost/m3 (as previous) = RM 112.22 Mixing cost by mixer/m3 (as previous) = RM 12.80 Cost for hoisting & placing by crane 11/23/2018 Concrete Mixing on Site using Cement, Sand & Aggregate

Ready Mixed Concrete 11/23/2018

READY MIXED CONCRETE Ready mixed concrete Concrete is ready mixed in the factory and will send to site by supplier 11/23/2018 Ready Mixed Concrete

READY MIXED CONCRETE Build up rate for 1m3 ready mixed reinforced concrete Grade 25 in isolated beams Assumption: Rental crane 15 tonne = RM 400.00/day (inclusive operator & fuel) Crane output to placing = 15m3/day 5 general worker to hoist & placing Ready mix concrete = RM 200.00/m3 (inclusive delivery to site) Allow 5% concrete wastage 11/23/2018

Reinforcement 11/23/2018

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 11/23/2018

RE-BAR LABOUR Output general worker 1.50 hr for 1 tonne bar Output for cutting, bending (Table 4) Output for placing (Table 5) 11/23/2018

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 40.00 per day Cutting, bending & placing = RM 60.00 per day 11/23/2018

FABRIC REINFORCEMENT MATERIAL Allow 5 % wastage Allow 10% for tying bar Allow 10% for lapping 11/23/2018

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 11/23/2018

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 40.00 per day Cutting, bending & placing = RM 60.00 per day 11/23/2018

Formwork 11/23/2018

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 11/23/2018

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 11/23/2018

LABOUR Determine sawn formwork or wrought/wrot formwork Add 25% for wrought formwork Output to prepare, placing and take out 11/23/2018

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 11/23/2018 11/23/2018

THE END 11/23/2018