This civil construction procedure applies to insitu industrial ground floor slabs with a tolerance of± 3mm or tighter.
Prior to placing subcontract concrete order check the specification to ensure the full extent of tolerances and surface finish is understood.
Concrete pouring order to be placed only when all parties have agreed tolerances, method of checking slab and acceptable remedial actions in the event of non-compliance.
Levels of ‘superflat’ floors (tolerance less than ± 3mm in 3m) to be checked using a parallel plate level.
Check readymix plant capability i.e.
- Plant inspection
- Assessment of mix
- Approval of design mix
- Capability to provide quantity/quality/type of mix
- Technical back-up
A method statement is to prepared and approved by the Project Manager prior to commencement of work.
Method statement may be submitted for approval by the consultant.
The concrete method statement will include proposed plant, labour levels, mix design, jointing details, sequence of pour, full details of guaranteed tolerances, any remedial works required to achieve tolerances.
Particular attention is to be paid for ensuring:
concrete level of reinforcement
pour sizes and sequence
achievement of surface finish, within tolerances
Check all materials on site i.e.
- Polythene as specified
- Mesh and bar reinforcement
- Joint Formers and dowel bars
Procedure organized for checking of loads.
Procedure agreed for reject loads.
Procedure agreed for checking and signatures.
Joint placement agreed.
Dowel bar setting agreed.
Powerfloat approximate start/finish time agreed.
Curing method agreed.
Saw cutting timing agreed.
Prior to commencing each pour check sub-base at least 1m beyond pour fully compacted and to correct level.
Check sand blind and final roll.
Check polythene positioned and laps correct.
Position and level road forms or screed rails.
Pour starts early enough to allow sufficient time for finishing trades.
Truck cycle times are acceptable.
Marshalling of trucks organized.
Turning areas are available.
Preparation Check List
Sub-base agreed beyond pour.
Road forms or screed rail correct level.
Isolation joints complete
Compressor working and fueled up.
Airlines laid out and not damaged.
Pokers are working.
Distribution plant ready. Pump and hoses positioned, concrete skip cleaned out.
Beam vibrators all working.
Shovels/rakes and other hand tools available, including bull float, follow-up screed.
Back-up plant working.
Mesh pre-cut if not already placed.
Mesh properly spaced and correct level.
Mesh at induced joints pre-wired to stools.
Cast in items and box-outs fitted and to correct level.
Dowel bars ready. (Debonded, end caps form/joints)
Stop ends pre-made.
Power floats and trowels ready and working.
Saw cutter organized.
Cube moulds ready, oiled and covered. Thermometer ready for noting down temperature of concrete.
Cube tank available and to correct temperature.
Slump cones and associated equipment ready.
Straight edge cleaned and available.
Curing equipment/materials ready.
Washing out facilities available.
Joints marked on forms.
Chalk line available for saw cuts.
During and Immediately after pour
Check correct mix, slump temperature, etc.
Check reinforcement in correct position.
Check compaction carried out.
Check test cubes taken and logged.
Check line and level of forms and poured concrete.
Check dowel bars in correct alignment.
Check timing of floating off, etc.
Re-check slab for correct tolerance (3m straight edge).
Protect and cure concrete.
Day After Pour Checklist
Check slab for acceptable tolerances.
Action remedial works if required in consultation with the consultant.
Strike forms and saw cut joints.
Check for blemishes and grout loss, etc.
Re-position curing membrane for a minimum of 7 days.
Protect slab against damage. Do not store anything on slab.
Do not allow traffic for 7 days minimum.