for Concrete Floors on Grade
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for Concrete Floors on Grade |
1.0 General:
1.1 Qualifications: All work shall performed by a member in good
standing of the Concrete Floor Contractors Association of
Ontario who shall conform to the requirements of CSA A23.1
(current edition). [a list of current members is available
from the Association office at 905-582-9825 or the
Association website at www.concretefloors.ca].
1.2 Related work: Earthwork, Formwork, Reinforcing Steel and
Miscellaneous Metals.
1.3 Work included: Concrete slabs on grade, slabs on metal deck,
concrete fill to metal pan stairs including non-slip inserts,
equipment pads, curbs, steel fibre reinforcing, concrete supply,
formwork including dowels, floor finishing, surface hardeners
and treatments, curing, sawcutting, isolation joints, and
caulking of floor joints.
1.4 Quality Assurance and Warrantee: It is the intent of
this section to establish a single competent source, being
the concrete floor finishing subcontractor, to be responsible
to provide complete durable concrete floors including the
provision of: formwork, reinforcing, concrete supply and
finishing labour complete as specified herein. Concrete
floors shall have an extended guarantee against surface
deterioration and cracking for a period of two years from
substantial performance of the work.
1.5 Pre-Construction Meeting: No later than three weeks prior
to the start of work on site, arrange for a special meeting
of all parties including the Owner’s representative, general
contractor, testing company, concrete supplier, floor
finishing subcontractor, earthworks subcontractor and
specialty material suppliers, to review the project drawings,
specifications and site conditions. The floor finishing
subcontractor shall submit a materials summary and a sawcut
and construction joint shop drawing for review and approval
by the Owner’s representative prior to any work being
performed on site.
[Reference: CFCAO Preconstruction Meeting Agenda Form]
2.0 Materials:
2.1 Concrete shall conform to CSA A23.1 having a minimum strength,
of 25 MPa [or higher as required per the structural design],
minimum 265 kg cement content, a maximum 0.55 water:cement ratio,
60 mm ± 20 mm initial slump, normal setting plasticizing
admixture to a final 130 mm ± 20 mm slump, 40 mm coarse
aggregate for slabs screeded with a laser screed machine and
20 mm coarse aggregate for slabs screeded by hand.
All admixtures shall be normal setting and non-retarding.
A maximum 10% slag or flyash cement replacement shall
be acceptable in all weather conditions with up to 25% slag
cement replacement or 15% fly ash in hot weather conditions.
2.2 Steel fibre reinforcing: conforming to ASTM A820.
2.3 Tolerances: As specified by CSA A23.1 [to meet
the requirements of the operating environment]. Conformance
measurement shall be completed within 72 hours of floor
installation.
2.4 Isolation joints shall be 6 mm thick flexible foam material
for perimeter walls and 12 mm thick for column wrapping and slab
penetrations.
2.5 Bulkheads: Steel or wood.
2.6 Dowels: Round or square smooth steel bars with bond breaker
on one end to allow horizontal slippage.
2.7 Dry Shake Surface hardeners: Factory pre-mixed incorporating
plasticizing agents [traprock / silica-quartz / emery /
metallic / coloured] applied at a rate [light duty: 3.0 Kg
per m˛ / medium duty: 5.0 Kg per m˛ / heavy duty: 7.0 Kg per
m˛] as shown on the drawings. [Note: Coloured hardener to applied
at a rate of 7 kg/m2]
2.8 Surface Evaporation Reducers: Confilm by Master Builders or
Eucobar by Euclid.
2.9 Curing compound: Clear, water based, non-yellowing
conforming to ASTM C-309 with a minimum solids content of 20%.
2.10 Polyethylene curing sheet to be a minimum of 0.05 mm thick.
2.11 Liquid Hardeners: penetrating hardening/dustproofing sealers
shall be applied at a 200 sf per gallon coverage rate in a
single flood coat application. [Note: Liquid hardeners do not
conform to ASTM C309 and are not to be used as a curing agent].
2.12 Sawcut fillers:
Type 1: for interior non-vehicular areas 12mm deep on a backer
rod using a flexible 2 component epoxy/urethane material
having a Shore "A" hardness of 25-35.
Type 2: for interior vehicular areas filled full depth of
the sawcut using a semi-rigid polyurea or epoxy filler having a
minimum Shore "A" hardness of 75.
3.0 Execution:
3.1 Provide sufficient lighting as necessary for finishing
requirements.
3.2 Inspect the granular base elevation for variations in excess
of +/- 10 mm in accordance with CSA A23.1 (to be repaired by the
earthworks subcontractor).
3.3 Protect adjacent surfaces from staining.
3.4 Install isolation joint for full slab thickness where slab
edges meet vertical elements (walls, columns, bollards etc.).
3.5 Isolate through-slab penetrations with sonotube for the full
depth of the slab. Fill with concrete no sooner than 28 days
after the adjacent slab has been cast.
3.6 Bulkheads shall be constructed for the full slab thickness,
straight and level with the finished floor elevation and shall
be located outside of traffic areas where possible. Dowels shall
be installed in the centre of the floor aligned to permit horizontal
movement and de-bonded on one end. All construction joints shall
be dowelled.
3.7 Add steel fibre reinforcing at the specified rate in
accordance with the manufacturers instructions. The concrete
floor contractor shall certify that the total quantity of
materials are added as specified. Steel fibre shall be added
to the concrete mixer truck to the next highest half bag increment
such that no less than the specified dosage rate is installed in
each truckload of concrete. All personnel who add steel fibre
shall have completed the CFCA Steel Fibre Certification Course.
3.8 Place concrete in accordance with CSA A23.1.
3.9 Finish concrete surfaces accordingly to specified tolerances.
3.10 Apply liquid surface evaporation reducers by sprayer to
protect the concrete from pre-mature surface drying when
required. Mix in accordance with the manufacturers
instructions and apply in a thin film following the
bull floating operation. Do not work liquid materials into
the surface of the plastic concrete.
3.11 Apply dry [pigmented] shake surface hardeners in multiple
applications to the total specified quantity [_____ Kgs/m˛].
Scrape any build-up of dry materials to achieve a uniform
coverage rate. Material manufacturer to certify that
materials are applied as specified.
3.12 Curing shall commence as soon as possible.
Type 1: Apply one coat of curing compound evenly across the
entire floor surface at the manufacturers recommended coverage
rate.
Type 2: Wet cure with poly, burlap or geotextile fabric.
Note: Surfaces to receive liquid hardeners or applied finishes shall
be wet cured.
3.13 Sawcut contraction joints at a maximum spacing of 4.5 lineal
metres on centre to a depth of 1/3 the slab thickness [38 mm
deep for Soffcut dry sawing] in approximately square sections.
Cutting shall commence as soon as possible, generally within
12 to 24 hours of concrete placement, depending upon ambient
conditions and the method of cutting.
3.14 Fill exposed sawcuts subject to solid tire forklift traffic
full depth with a load bearing polyurea or epoxy filler (without
backer rod) a minimum of 120 days after floor installation.
3.15 Fill exposed sawcuts subject to foot traffic, where specified,
with a flexible epoxy/urethane sealant 1/2" deep on a backer rod a
minimum of 75 days after floor installation.