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Architectural Concrete Finishes Concrete Floor Contractors

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Architectural Concrete Finishes Concrete Floor Contractors Powered By Docstoc
					   Architectural Concrete Finishes
Geoff Kinney                             Brian Salazar, C.E.T.
Executive Director                       National Business Development Manager
Concrete Floor Contractors Association   Euclid Canada Inc.
                                The Best Floors Start
        The CFCA                 With Our Finish !TM




• Founded in 1972.
• Represent major concrete
  floor contractors and
  materials suppliers
  across Ontario.
• Provide technical
  assistance to specifiers
  and contractors.
• Our goal is to assist you
  with obtaining high quality
  results (and avoid
  problems !).
                                                       Metro
                Agenda

•   The process of obtaining high quality
•   Colouring
•   Textures
•   Problem Areas
•   Resources
         “Architectural” Concrete

• Falls into a different category than regular concrete
  flatwork because the focus is on quality and not speed.
• It is essential to carefully select all participants.
• Site conditions vary widely and require careful
  management.
• The right attitude, effort and care is critical for success.
• Exposed concrete finishes are sustainable solutions.
           Quality is a Process
                             Design




     Ambient & Site                               Trade
      Conditions                                Contractor
                             Attitude:
                             Sincere
                            intentions
                             & efforts



                                         Materials
               Inspection
                                         Supplier


• A weak link can lead to reductions in quality.
• A broken link can stop it from being achieved entirely.
• Quality and attitude are strongly correlated.
                  Workmanship
• Management of workmanship is often the weakest link.
• Too little prequalification is done in specifications beyond
  the general contractor.
• There is a great need to complete the work to defined
  industry standards (eg: ACI FF & CSA).
• CFCA members are quality leaders.
• The CFCA is here to support your efforts.




                        Metro
          Materials Selection
• Materials selection should be based upon a
  variety of factors including workability and
  durability.
• A list of the materials should be submitted
  by the trade contractor (which can be used
  by inspectors).
• Beware material substitutions (which are
  common but not always of equal quality).
             Specifications
• Need to be clear and precise.
• Should pre-qualify and name trades on
  tender forms.
• Should stipulate the acceptability of
  alternates or any performance requirements
  that need to be met.
• Must specify mock-ups and a pre-
  construction meeting.
• Must include a full scope of work (including
  concrete supply).
       Traditional “Divided”
          Scope of Work
                          Earthworks
                          Contractor
    Forming                                    Materials
   Contractor                                  Suppliers



  Sawcutting                Prime             Reinforcing
  Contractor              Contractor          Contractor



   Concrete                                     Caulking
   Supplier                                    Contractor

                          Concrete
                          Finisher

Divided responsibilities = multiple opportunities for problems
    Pre-Construction Meetings
                = Avoid Problems !
Are required to ensure:      • Review the mock-up.
• The Owner’s/specifiers     • Review the joint details
  expectations are
  understood.                  and layout.
• Held on-site.              • Review the QA
• Review the condition of      inspection procedures.
  the building envelope
  and ambient conditions.   Must invite: The Owners rep,
• Review the specified      GC, concrete producer, finisher,
  methods & materials.      testing firm, and any major or
• Review the associated     unique suppliers.
  work of other trades.
       Minimum 1 month prior to pouring
                  Key Issues
• Safety including           • Scope of work.
  ventilation.               • Joint shop drawings.
• Ambient Conditions.        • Mock-up approval.
• Temporary services         • Concrete mixes.
  including water, lights,   • Granular base elevations.
  and vented heat.
                             • Schedule of placements
• Specifications &             and joint filling.
  tolerances.
                             • Site walk-through.
• Drawings and details.
                             • Any perceived problems
• Materials to be used.        or concerns by anyone
• Methods of construction.     (speak up now & not
                               later).
            Inspection Items
                                                     !
• INSPECTION IS CRITICAL TO SUCCESS !!!
• Inspectors are part of the quality team.
• Full time inspection on pour days is an investment in
  quality.
• Inspect and record the quantity and source of all
  materials being used (fibres, sealers, plasticizer,
  hardeners, concrete etc.).
• Site inspection letters can be requested from major
  materials suppliers.
• Inspection stops mistakes, last minute substitutions
  and ensures value for your money !
            Mandatory Standards

• CSA A23.1-04 Concrete Materials & Methods of
  Concrete Construction (new version in 2009)
• A23.3-04 Design of Concrete Structures
• S269.3-92 Concrete Formwork
• S413-07 Parking Structures
• S448.1-93 Repair of Reinforced Concrete in Buildings
• A3000-08 Cementitious Materials

Note: CSA Standards are mandatory in Canada through inclusion in
national and provincial building codes.
              Concrete Mixes

• Concrete constituents are changing rapidly to reduce the
  carbon footprint of cement.
• Cement is being partially replaced with “slag” and
  “flyash” by-products creating new protection, finishing
  and durability concerns:
   • Slag = steel manufacturing by-product (up to 25% for floors).
   • Flyash = coal burning by-product (up to 15% for floors).
   • GUL = limestone dust cement (up to 15% for everything).
• Lower cement contents create longer drying periods for
  applied finishes and lower wear resistance.
• 30 MPa, 0.55 w/c, low water content plasticized concrete
  is ideal.
                  Reinforcing

• Unreinforced concrete is NOT a good solution.
• Micro-synthetic fibres provide plastic shrinkage
  protection only.
• Dowels may be used to reinforce joints only.
• Wire mesh must not be permitted to settle to the base.
• Steel and macro-synthetic fibres are generally not a
  good solution for architectural pavements.
• Rebar reinforcing may not be a good solution for
  exterior applications due to long term corrosion.

       ALL joints MUST be physically connected !
                      Mock-ups
• Must be representative of
  the final product (not too
  small).
• MUST BE $PECIFIED.
• Samples are required to
  ensure that expectations
  of the Owner/specifier
  can be met.
• No architectural work
  should proceed until this
  critical step is completed.
                Granular Bases

• Compaction must be
  uniform.
• Elevations vary and are
  not being thoroughly
  checked on many projects.
• Base elevations “shall” be
  within ±10 mm (CSA
  A23.1).
• Thickness control is
  essential for good slab
  performance.
• NEEDS more inspection.
       Joint Shop Drawings
• Joint layout is critical to
  minimize cracking.
• Discuss at preconstruction
  meeting.
• 4 types:
                                                         Standard                                                             6mm Foam Isolation Joint
                                 Giffels                 Perimeter Column
                                                         Isolation Joint Details
                                                                                                                                    (Typical)


                                 Columns require careful isolation from a
                                 concrete floor in order to avoid cracking
                                 caused by restraint.




   • Isolation
                                 Similarly, other through-slab vertical
                                 elements also require isolation from the
                                 concrete to avoid problems related to
                                 the drying shrinkage of the concrete.

                                 These details should be submitted for                                          Asphalt coating on
                                 approval by the Concrete Floor Contractor                                      base plate, anchor
                                 for each project.                                                              bolts & column below
                                                                                                                finished floor.




   • Construction
   • Contraction
                                                                                               6mm foam
                                                                                                 typical                                 Infill ONLY after
                                              Sawcut                                                                                     adjacent sawcuts
                                                                                      Sawcut
                                                                                                                                         have cracked.

                                 Wide Flange Columns:                        HSS Columns:                  Wind Columns:
                                 Wrap with rigid 12mm asphalt                Wrap with 6mm foam.           Isolate columns which do not align
                                 impregnated fibre board.                                                  with sawcut layout using sonotube.




   • Expansion (exterior only)
           Floor Flatness/Levelness
• Floor tolerances MUST
  be listed in Division 3.
• FF20/FL20 is a
  conventional flatness
  tolerance specification.
• FF30/FL20 is a “flat” floor
  tolerance specification for
  exposed surfaces or thin
  applied finishes.
• Tolerances MUST be            F Number tolerances are:
                                • Systematic
  measured in 72 hours for      • Repeatable
  acceptance/rejection          • Practical
  purposes.                     • Informative
                    Curing
• Curing is the process     • Wet curing is ideal.
  of providing sufficient   • Avoid multiple coats of
  water for the cement to     sealers which can
  harden properly.            create slippery
• Lack of curing creates      conditions in outside
  weak/dusty surfaces.        pavements.
• Curing is never           • Curing membranes are
  optional.                   not durable and will
                              require maintenance.
                            • Liquid hardeners are
                              not curing agents.
      Concrete Floor Finishes
Colouring:
• Surface Applied
• Integral
• Stained / Dyed Concrete
Textures:
• Traditional
• Exposed Aggregate
• Impressed (Stamped)
  Concrete
• Polished Concrete
• Toppings
Sealers:
• Liquid Densifiers
• Surface Sealers
              Surface Colouring

• Dry surface application
  of aggregates with or
  without pigment.
• Increased wear
  resistance (2-4 x).
• 6 kgs/m² is the ideal
  coverage rate.
• Ideal for interior
  applications.
• Can produce light
  reflectivity.
      Light Reflective Hardeners

• Originally developed for
  aircraft hangers.
• Light reflective pigments
  can improve light levels.
• Reduce fixture
  investment, maintenance
  and energy costs.
• Increased surface wear
  resistance.
           Integral Colouring

• Coloured throughout the
  entire slab thickness
  (may also be applied as
  a coloured topping).
• No improvement in
  wear resistance.
• No effect on freeze
  thaw durability.
• Ideal for exterior
  applications.
               Stained Concrete
• Permanent.
• Non-uniform in colour.
• Chemically etched.
• Can be combined with a
  polished concrete finish
  or acrylic sealer.
• Multiple colours.
• New or existing
  surfaces.
                 Dyed Concrete
• Permanent.
• Uniform in colour.
• Can be combined with a
  polished concrete finish or
  acrylic sealer.
• Multiple colours.
• New or existing surfaces.
                    Textures

•   Traditional Finishes
•   Exposed Aggregate
•   Impressed Concrete
•   Coloured Concrete
•   Stained Concrete
•   Polished Concrete
•   Liquid hardeners /
    sealers
         Traditional Finishes

• Broom finish
  (sidewalks &non-slip
  areas)
• Hand swirl float
  finish (walks &
  decorative
  pavements)
• Machine float finish
  (pavements)
     Exposed Aggregate

• Can be either seeded or
  integrally mixed.
• Many colours of
  aggregates.
• Concrete can also be
  integrally coloured.
• Non slip.
             Imprinted Concrete
            Imprinted, “INCRETE” TM, “Patterned”    , “Bomanite” TM
                                                   TM




• Many patterns.
• Many surface or integral
  colour options.
• Various accent colours.
• Looks very much like
  real stone, but it is
  concrete.
             Skin Texturing

• No predefined
  patterns.
• Sawcuts are used
  for control of drying
  shrinkage and to
  create patterns.
• Can be natural
  coloured or
  pigmented.
               Mortar Toppings

• Multiple colours.
• Multiple textures.
• No predefined
  shapes.
• New or existing
  surfaces.
              Polished Concrete
• High shine, low
  maintenance finish.
• Concrete can be plain,
  stained/dyed or
  pigmented.
• Eliminates an applied
  finish and associated
  future maintenance costs.
• Liquid silicate densified.
• Does not scrape off like a
  coating.
    Polished Concrete Floors


Before:




After:
                     Polish Levels
                                     L1

• Various systems in the
  marketplace with
  different definitions.
• 3 distinct levels of final
  polish:                            L2
   1. Matte
   2. Semi-gloss
   3. High gloss




                                     L3
      Aggregate Exposure




• Polished concrete is a surface treatment.
• Aggregate exposure needs to be CLEARLY defined in
project specifications for exposed aggregate “terrazzo” type
applications.
                Liquid Densifiers
• Chemically reacts with
  hydrated cement to densify
  the surface.
• Does not scrape off like a
  coating.
• Will develop a sheen with
  power scrubbing over time.
• Inexpensive compared to
  traditional coatings.
• Can be applied as a burnish
  coat for a quick gloss.
                Sealers

• Acrylic: inexpensive, clear, relatively soft,
  easy to re-seal.
• Epoxy/Urethane: clear, pigmented, wear
  and chemical resistant, more complicated
  to re-apply.
• Wax: as used on tile finishes (cost and
  labour intensive).
          Endless Combinations

• The only limitation is
  your creativity.
• The combination of
  colours and textures
  is limitless.
• Manufacturers can
  also assist you.
     GREEN Concrete Floors

How ?                       Options:
• Better decisions on       • Concrete as an
  labour & materials          exposed finish.
  through “Single           • Optimized slab
  Source” Specifications.     designs.
• Reducing energy           • Light reflective floors.
  needs.
• Eliminating solvents.
• Improving durability
  and reducing
  maintenance.
       Major Problem
     Improvement Areas


•   Coordination & accountability.
•   Lack of reinforcing.
•   Applied finishes issues.
•   Freeze that durability
               Coordination

• Schedules are shorter than ever.
• Site conditions are generally poor.
• Coordination between trades is often minimal.
• Planning time is almost non-existent due to last
  minute awards of work.
• Division of responsibilities are creating
  problems.
                 “Single Source”
                     (Undivided Scope)

                                           For all critical surfaces:
                                           • Architectural finishes
    Earthworks             Prime           • Superflat floors
    Contractor           Contractor        • Rink slabs




                                         • Undivided responsibility
                        Concrete Floor   • Single warrantee
                         Contractor      • No conflicts
Earthworks       Forming        Place & Finish      Concrete
Inspection       Operation       Operations         Mix Supply

Materials        Reinforcing      Sawcutting         Caulking
Selection         Design          Operation          Operation
         Slab Design
• Unreinforced concrete
  cracks easily and often
  moves differentially at joints
  (repairs ≠ green).
• It is generally not possible
  to repair architectural
  concrete seamlessly.
• Reinforcing the joints
  produces long term
  durability.
      Performance MUST
      also be considered !
  Lack of Reinforcing
 Uneven joints are a common & major failure




                                         Wire mesh works
                                        if it is placed within
                                             the concrete !

Dowel across all joints and between pours !
               Vapour Retarders
                   Barriers

• To reduce future delaminations of non-
  breathing finishes due to vapour movement.
• Located directly under the concrete slab.
• Will aggravate curling and cracking.
• Should be reinforced and use low slump
  (plasticized) concrete.
• Review schedule of applied finishes at the
  preconstruction meeting.
             Drying Time for
             Applied Finishes

• Unused concrete mix water equals 0.5 litre/sf.
• Do not use a curing membrane (wet cure for 3
  days).
• Protect the slab from environmental re-wetting.
• Minimize slab thickness.
• Decrease the water:cement ratio of the concrete to
  between 0.40 and 0.45 (less water + plasticize &
  increase cement content).
• Avoid lightweight concrete aggregates (if possible).
      Freeze Thaw Durability

• See CSA A23.1 for the correct mix.
• Concrete needs the correct w/c, air entrainment,
  strength and durable aggregates to perform.
• Exterior concrete requires 28 days of air drying
  to have sufficient freeze thaw durability.
• Curing is critical to obtain good surface durability
  (Minimum 10°C for 7 days).
• Minimize SCM’s.
On the Web
Technical Library
               Summary
• Specify full “single source” scopes of
  work.
• Prequalify your trades.
• Hold pre-construction meetings !
• Inspect everything to ensure value.
• Exposed concrete floors are a
  sustainable solution.
• The CFCA is here to help you !
- Shouldn’t yours ?



                  Metro

				
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