The Best Floors Start With Our Finish !

Concrete Floor Contractors Association

Concrete Canada

What is the CFCA ?

• The CFCA is the technical voice of the concrete floor industry.

• CFCA provides design assistance to owners & specifiers.

• CFCA contractor and materials suppliers are concrete floor industry quality leaders.

• The CFCA is a proven pre-qualification tool for specifiers.

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Exposed Concrete floors are

THE Sustainable Floor Solution

• Concrete floors are already

part of every building.

• Concrete is both

economical and durable

(low maintenance).

• Good design, materials,

workmanship &

coordination are

necessary.

What makes a good floor ?

The correctly defined & executed combination of

materials & workmanship to meet your clients needs with

sincere consideration for responsible sustainability

(including durability & future maintenance).

“To meet the needs of the present without compromising the ability of

future generations to meet their own needs” USGBC

03345 Specification

• A separate “concrete floor” specification is

necessary which includes all related concrete

floor materials, tolerances and finishes.

• While specifications define the framework for

success – they do not build great floors.

Coordination

• Schedules are short.

• Planning time is almost non existent due to last minute awards of trade work.

• Conditions vary significantly between sites.

• Division of responsibilities create problems.

good materials

+ good workmanship

+ poor coordination

= quality & performance

problems

Concrete

Placing & Finishing

Contractor

Reinforcing

Contractor

Forming

Contractor

Earthworks

Contractor

Concrete Mix

Supply

Sawing Contractor

Material

Suppliers

(multiple)

Caulking

Contractor

Divided responsibilities = opportunities for coordination problems

Your

Floor

Divisions of Responsibility

Curing & Sealing

Contractor

Polishing

Contractor

Concrete Floor

Contractor

Prime

Constructor

• Undivided responsibility

• Single warrantee

• No finger pointing

“Single Source” Scope

For all critical surfaces:

• Architectural finishes

• Rink slabs

• Superflat floors

• Higher quality anything

Reinforcing

Forming

Earthworks

Subcontractor

Jointing

Material

Suppliers

(multiple) Caulking

Curing & Sealing

Polishing

Placing

Finishing Concrete Mix

Putting the pieces together correctly & efficiently

Base elevations

poor workmanship

+ good materials

Why Prequalify ?

good workmanship

+ cheap materials

The selection of good materials

& good trade contractors

is critical for success !!

= quality & performance problems

Two Types of Floor Crews The Cowboys

• Hard working but don’t read

specifications or technical standards.

• Substitute specified materials with

whatever was left over from the last job.

• Only care if they get paid.

• No guarantees – they left town yesterday !

The Professionals

• Are skilled and technically proficient.

• Use specified methods & materials.

• Identify and resolve problems before

they become part of the finished work.

• Stand behind their product with pride.

• Provide a written guarantee.

Quality Materials

• High quality materials are an essential input in high

quality (sustainable) construction.

• Beware “unapproved equal” substitutions.

• All materials are not equal in cost or performance

and requires careful analysis (consultation).

• CFCA members are industry quality leaders.

Pre-Construction Meetings

• To ensure that the Owner’s/specifiers expectations are understood clearly.

• Must be held on site.

• Must include participation by all parties – including the concrete floor contractor.

• Provides an opportunity to express concerns prior to construction.

Review:

• Responsibilities of parties

• building envelope and ambient conditions.

• specified methods & materials.

• Concrete mix

• mock-ups.

• joint details and layout.

• inspection procedures.

• work of other trades.

Coordination Checklist

• There are almost 50

items to review for any

floor installation.

• Divisions of responsibility

increase problems.

• Scopes of work need to

be more inclusive.

Concrete Mix Submissions

• Review all the

ingredients and

proportions carefully.

• The mix needs to be

designed for use as a

floor (not just

compressive strength).

• CSA A23.1 compliant =

maximum 0.55 w/c.

Canadian Construction Association

Must be carefully reviewed in

terms of type and location.

• Construction Joints

• Isolation Joints

• Contraction Joints

• Expansion Joints

(exterior only)

Joint Layout / Shop Drawings

HSS Columns:

Wrap with 6mm foam.

Wide Flange Columns:

Wrap with rigid 12mm asphalt

impregnated fibre board.

SawcutSawcut

Wind Columns:

Isolate columns which do not align

with sawcut layout using sonotube.

GiffelsStandard

Perimeter Column Isolation Joint Details

Asphalt coating on

base plate, anchor bolts & column below

finished floor.

6mm Foam Isolation Joint

(Typical)

Infill ONLY after adjacent sawcuts

have cracked.

6mm foam

typical

Columns require careful isolation from a

concrete floor in order to avoid cracking

caused by restraint.

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 approval by the Concrete Floor Contractor

for each project.

Mock-ups

• Are co$tly and must be

specified.

• Must be representative

of the final product (not

too small – or too

perfect).

• Samples are required to

meet expectations.

MUST be mandatory for all exposed/architectural work

Inspection

• INSPECTION IS CRITICAL TO SUCCESS !!!

• Inspectors are part of the quality team.

• Full time inspection on pour days is an investment in quality – not an optional expense.

• Inspect and record the quantity and source of all materials being.

• Site inspection letters can be requested from major materials suppliers.

• Inspection stops mistakes, last minute substitutions and ensures value for your money !

! If you don’t check it – you may not get it !

Inspection Items

• Obtain a list of materials to be used at the P/C meeting.

• Inspect and verify the quantity and product names of all materials being used on site.

• Inspect the elevation of the granular base.

• Check the air content of all concrete.

• Ensure that inspectors are instructed to advise of any deficiencies immediately when they are observed.

!

Inspection catches mistakes,

stops cheaters and ensures value

CSA A23.1-2009

Our national mandatory concrete standard.

• Granular base elevation tolerances (±10mm).

• Slab thickness tolerances (> T - 10mm overall and > T -

20mm or R&R).

• Designing for curling.

• Vapour retarders.

• Concrete mix (maximum 0.55 w/c for floors).

• Concrete batching, handling and testing information.

• Floor surface tolerances (FF20/FL15 etc.).

• Bonded toppings.

Concrete Mixes

• Cement & concrete constituents are changing rapidly to reduce the carbon footprint.

• The need to manage concrete materials is essential - these new materials require careful design, ordering and handling for success.

There is no such thing as “normal” concrete anymore

Concrete Mixes for Floors

• Compressive strength has little

relationship to finishability, wear

resistance, drying time, moisture

permeability and drying shrinkage

curling and cracking.

• CSA A23.1-2009 mandates a maximum 0.55 water:cement ratio (minimum paste quality).

Drying Time for Applied Finishes

• A 25 MPa “compressive strength” mix is a ± 0.67 w/c (160/240).

• A CSA “standard” residential concrete floor mix is a 0.65 w/c.

• A CSA “standard” ICI concrete floor mix is a 0.55 w/c.

• Drying time for a 100mm SOG to reach 3lb/000sf/24hrs:

– 0.4 w/c: 2 months

– 0.5 w/c: 6 months

– 0.6 w/c: 1 year

• Thickness factor (based on 0.5w/c):

– 100mm to 150 mm: 2 times longer

Calcium

Chloride Test

RH Sensors

Tramex

Moisture

Metre %

SCM’s

• Pozzolans versus hydraulic cements.

• Slag cement: ground steel slag by-

product (hydraulic).

• Flyash: from coal burning powerplants

(quality varies): 2 types !

– Type C (hydraulic)

– Type F (pozzolanic)

• Silica Fume: from silicon metals

manufacturing in electric furnaces

(pozzolan).

• GUL Cement: Inter-ground limestone dust

(pozzolan).

(Cement Replacing / Extending Materials)

Slag

Flyash

Silica Fume

Portland Cement

SCM % for Floors

• Cement contents for floors are relatively low - hydraulic

cements are necessary !

• Without requiring the use of chemicals & water fog

spraying.

– Summer: FA[h]/15 + S/25 ≤ 1.00

– Winter: FA[h]/10 + S/10 ≤ 1.00

* Using Type C hydraulic [h] flyash

• CAUTION: New “GUL” cement adds up to 15% cement

replacement automatically (+ SCM’s ??).

Plastic Protection

• “GREEN” & other high-tech

concrete mixes have new

set & plastic properties (low

bleed rates).

• More mixes must now be

protected immediately after

concrete placement.

• Concrete mixes can be

designed to reduce or

eliminate this need.

Concrete Slump

• The slump at the point of deposit should be a minimum 100 mm for consolidation and screeding (+ H&S).

• Concrete for floors should be plasticized to reduce shrinkage (with water reduction).

• All fibre reinforced concrete require plasticizers to over-come mechanical slump loss.

Air Entrainment

• Protects the paste from deterioration in

freeze/thaw cycles.

• Is not required for interior freezers or rink

slabs.

• Must not be machine trowel finished.

• Must be measured at the point of deposit.

• Air contents should be checked for non-air

entrained concrete too.

• Is not compatible with the application of dry

shake-on surface hardeners.

Granular Bases

• Elevations “shall” be within

±10 mm.

• “The concrete floor

contractor shall not be

responsible for any liability

associated with slab

thickness reductions as

caused by incorrect

granular base elevations or

changes in slab thickness

caused by soft spots (eg:

rutting). “

Major Problem

Poor QC

Slab Thickness

• Acceptable if the average thickness is not more than

10 mm less than the specified thickness.

• No individual measurement is more than 20 mm less

than the specified thickness.

• “Should” be taken within 7 days of each floor

placement to avoid compounding of any problems (ACI

117 = “shall”).

Vapour Barriers Retarders

• To reduce future delaminations of non-breathing finishes due to vapour movement.

• Located directly under the concrete slab.

– Will increase shrinkage.

– Will reduce drying time for applied finishes.

• Changes to the concrete required (less water without loss in workability).

• Maintain restraining reinforcing.

• Review schedule of applied finishes at the pre-construction meeting.

• Follow manufacturer’s instructions !!!

Floor Reinforcing

• Unreinforced designs must reinforce joints.

• Micro synthetic fibres for plastic shrinkage.

• Normal Gauge wire mesh is impractical to

install at a fixed elevation.

• Macro synthetic fibres for light traffic &

loading.

• Steel fibre reinforcing for light to heavy traffic

and loading.

• Rebar heavy loads and jointless floors.

• Post tensioned designs uncommon.

Steel is the best thing that ever happened to concrete !

Sustainability: Design for long term performance

Curling

• Curling occurs at all floor joints through differential drying shrinkage between the top and bottom of a slab.

• Costly to repair for applied finishes – can ruin an exposed architectural finish.

• Restrain curling with reinforcing !

CSA: “Owners shall specify low-shrinkage concrete mixes, appropriate

curing, or suitable reinforcing, or a combination of these, as necessary

to minimize curling to suit their intended usage”.

Sawcuts

Differential Joint Movement Uneven joints are a common exterior failure

Dowel between pours reinforce across joints

• Unreinforced concrete is problematic.

• Micro synthetic fibres DO NOT reinforce

hardened concrete against joint movement.

• Performance must be considered in design

for all exposed concrete work.

Steel Fibre Reinforcing

• Practical & economical.

• Turns brittle concrete into a ductile material.

• Can restrain curling forces effectively.

• Will not interfere with wire guidance systems.

• Some fibres are ULC rated for slabs on deck.

• Is durable in exterior applications.

• Can spot rust in corrosive environments.

Steel Fibres

• All fibres are not equal in

performance – do not substitute

alternatives without a design

review !

• Steel fibres must be supplied

with a “certificate of

conformance” and “test reports”

as per ASTM A820.

Various Fibres

Every Fibre Type is Unique

• Each floor loading condition is designed using a single fibre type resulting in a specific dosage rate for that particular fibre’s performance.

• 20 kgs SFR ≠ 3 kgs marco synthetic fibre.

Drawn

Wire

Mill

Cut

is NOT

equal to

is NOT

equal to

Macro

Synthetic

Marginal Cost Analysis

• For any given set of loading

conditions there is an optimal

design.

• Plotted combinations of

concrete strength, slab

thickness, fibre type and fibre

dosage by cost.

• Best result:

Thinnest floor with 30MPa,

premium $ fibre @ 30 kgs/m3.

Surface Durability

• The surface of plain concrete is weaker than the bottom of a slab.

• Wear resistance is significantly increased by hardening the surface of the slab with hard aggregates.

• Good quality curing is essential to achieving superior surface durability (often not done).

Dry Shake Hardeners

• Mineral or metallic aggregates applied to the surface of freshly placed concrete.

• Applied at 3, 5 or 7 kgs/m2.

• Rates above 5kg/m2 may be impossible to install without utilizing special application techniques, specially designed concrete mixes and having suitable ambient conditions.

• 7 kg/m2 is the specified rate for pigmented hardeners.

Application Rates

60 lbs / 100 sf

[3.0 kgs/m2]

100 lbs / 100 sf

[5.0 kgs/m2]

Or

66lbs Agg. &

33lbs Cement

150 lbs / 100 sf

[7.0 kgs/m2]

Common Practice

5kgs/m2 is an ideal and practical application rate

Ideal

Relative Abrasion Resistance

0

50

100

150

200

250

300

350

400

450

500

Plain - Uncured

Plain - Cured

Hard Troweled

Liquid Hardened

NM Traprock

NM Silica

NM Emery

Metallic

The Concrete Floor Revolution

Light Reflective Floors

• Originally developed for

aircraft hangers to improve

light levels.

• Can reduce energy costs by

increasing light spacing –

reusing light.

• Increased surface wear

resistance.

• 7 kgs/m2 application rate.

Stencil Artistry

Polished Concrete

• High shine, low maintenance

finish.

• Concrete can be plain,

stained/dyed or pigmented.

• Eliminates an applied finish

and associated future

maintenance costs.

• Must be liquid silicate

densified to reduce porosity.

• Various aggregate

exposures.

Specification Bulletin

• Aggregate exposure:

– Class A, B or C

• Gloss level:

– Level 1, 2 or 3

Floor Tolerances

• Tolerances are poorly understood by many (& are not always measured).

• Can be based upon data taken from existing facilities.

• Tolerance losses caused by curling must be calculated into the design - consider applied finishes carefully.

• Each environment must be reviewed carefully (check lift truck data).

Shall be measured within 72 hours of floor casting !!!

1/8” in 10’ Tolerances

FF62

FF27 FF22

FF37

Straightedge tolerances are meaningless

Flatness & Levelness

Floor Levelness – (FL) Defines conformity to a

horizontal plane measured over 10’ (screeding

methods).

Floor Flatness – (FF) Defines a floors curvature over a

2’ length (finishing methods).

Bumpy Level Floor Bumpy Tilted Floor

-1500

-1000

-500

0

500

1000

1500

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241

Inc

he

s x

10

00

Half-Feet

Run 2 Profile

-1000

-500

0

500

1000

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241

Inc

he

s x

10

00

Half-Feet

Run 1 Profile

Examples

FF15/FL11*

-1000

-500

0

500

1000

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241

Inc

he

s x

10

00

Half-Feet

Run 17 Profile

FF48/FL35**

FF68/FL19*

-1000

-500

0

500

1000

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241

Inc

he

s x

10

00

Half-Feet

Run 5 Profile

FF91/FL70**

* Hand Screed

** Laser Screed

Elevation change

+/- 6mm

+/- 15mm

-70mm

+/- 3mm

Sloping Floor

Elevated Slabs

• Deflection levelness is a function camber and

dead load - not finishing techniques.

• Flatness significantly affects the appearance of

applied finishes.

• FF30 is the highest F Number that can be

achieved (specify FF25).

• Straightedge tolerances measure deflection &

camber and not flatness.

Superflat Floors

• Required for AGV defined-traffic floors and narrow-aisle high-rack warehouses and other special applications.

• Require the use of the “Fmin” system (NOT FF/FL).

• Placed in long strips without sawcuts (to avoid tolerance losses due to curling).

• Require reinforcing against longitudinal shrinkage and surface hardening without the use of aggregate hardeners.

FF30

FF117

Construction Joints

• Joints must be doweled with smooth bars /plates that are de-bonded and aligned to permit horizontal movement.

• Do not use deformed rebar.

• Do not use keyways.

Formed keyways

do not work

Contraction Joints

• Must be cut in a timely

manner and at a

sufficient depth to work.

• Maximum 4.5m spacing

at approx. 25 times the

slab thickness.

• Should be located at all

sources of stress

including: bollards,

columns, corners,

thickenings, pits, etc.

• Sawcuts may be added

over supporting

members in exposed

slabs on deck to

minimize cracking.

CAUTION: lightly / un-

reinforced concrete cracks easily !

Cracks

Many causes:

• High shrinkage concrete.

• Contraction joint spacing too far apart, too late or not deep enough.

• Points of restrain not isolated with cuts.

• Conduits cast into the slab.

• Contraction joints held together by bonded or deformed steel reinforcing.

• Granular base settlement.

• Concrete over-loaded / under designed.

Soffcut Sawcuts

• A specialized dry process.

• Cuts directly behind the finishing

operation before shrinkage starts.

• A 38mm deep cut can create a

crack in up to 300mm of concrete.

• Soffcut joints are shallow and less

expensive to fill full depth.

Joint Filler Details

Epoxy or

Urethane Sealants Epoxy

Fillers Polyurea

Fillers

Cannot displace

vertically

FOOT TRAFFIC

ONLY FORKLIFT TRAFFIC FORKLIFT TRAFFIC

** Soffcut joints require less filler materials = lower cost

**

May displace

vertically

Joint Fillers

• Floor joints subjected to hard wheel traffic should be protected from deterioration by filling full depth with a semi-rigid (min. Shore “A” of 80) load bearing filler after a minimum 120 days of drying.

• Joints subject to foot / light traffic may be sealed 1/2” deep with a more flexible sealant on a backer rod after 60 days of air drying.

• Use hot rubberized asphalt

filler for exterior joint filling

due to excessive thermal

movement.

• Fill freezer joints at operating

temperatures (do not pre-fill).

These joints are 4m apart.

Filler Timing

• Leave joints unfilled and

fill after a minimum 120

days of air drying at 20°C.

• “The requirement to

replace joint

sealants/fillers which de-

bond as a result of early

filling is not a

workmanship or material

deficiency.“

Curing & Sealing Membranes

• Are relatively soft – not

durable.

• Are only meant to retain

moisture to help cement

hydrate (harden).

• Should not be used with

penetrating or applied

finishes.

Liquid Hardeners

• Inexpensive.

• React chemically with the

CaOH over several months.

• Do not wear off with traffic =

maintenance free.

• Are not curing agents.

Before After

Application

• Spray versus flood coating.

• Applied at the time of

finishing.

• Applied after 3 days of wet

curing, wash & dry.

• Applied after 28 days of air

drying.

• Applied to old surfaces.

Concrete mixes with pozzolans also react with CaOH

Green Concerns

• “Green-washing” is a major problem (eg: coal

byproduct = green cement replacement / bleached

recycled paper / deleting reinforcing).

• Green changes are occurring VERY quickly.

• Properties of GREEN concrete are significantly

different than “normal concrete”.

• There is no measurement of actual performance (eg:

durability, repairs and maintenance).

• LEED is also creating some issues.

LEED Cement Issue

• Reductions in portland cement are rewarded.

• However - large increases in alternative cements

change the behavior of concrete (set, bleed rate,

finishing and shrinkage).

• 25 MPa x 10 factor = 250 kgs/m3 Cement

• 160w/250c = ±0.65 w/c (porous, high shrinkage & low

wear).

Compressive strength is NOT the

most critical concrete mix factor for floors

REMEMBER:

Drying to 3lbs/000sf/hr:

0.4 w/c: 2 months

0.5 w/c: 6 months

0.6 w/c: > 1 year Source: ACI 302

On the Web @ concretefloors.ca

Summary

• Exposed concrete floors are a very sensible and

sustainable solution.

• Specify fully inclusive scopes of work including concrete

supply & polishing for high quality results.

• Use pre-construction meetings to manage coordination

and expectation problems.

• Inspect everything to ensure value.

• Prequalify CFCA industry leaders in your specifications

for the best results.

Other References

• CSA A23.1 Concrete Materials and Methods of Concrete Construction.

• American Concrete Institute

– ACI 117 Tolerances for Concrete Construction

– ACI 302 Guide to Concrete Floors

– ACI 360 Guide to Design of Slabs on Ground

• Portland Cement Association *

• Concrete Floor Contractors Association website.

Contact Information

Concrete Floor Contractors Association

RPO DUNDAS NEYAGAWA, PO Box 30021, Oakville, ON, L6H 7L8

Tel: (905) 582-9825

Fax: (416) 981-3913

E-mail: info@concretefloors.ca

Website: www.concretefloors.ca

Windsor

London

Toronto