Specifications for Good Quality Concrete Floor - Tolerance REV J

8/10/2019 Specifications for Good Quality Concrete Floor - Tolerance REV J

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Face Construction Technologies, Inc.

CONCRETE FLOORS ASIA

Jeff Rogers

Specifications for Good Quality Concrete Floor Tolerance

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Why do we need good floors?

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Higher efficiency

Fewer trucks & operators needed

Increased productivity

More pallets moved each day

Reduced truck maintenance and breakdowns

Loads can be lifted and stored higher

Reduced floor maintenance

Less cracking & spalling

Clean and dust free

Safer to operate on -

Fewer wor

kplace injuries

Racking installation goes faster


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What is Flatness & Levelness?

FLATNESS (FF)

Relates to the bumpiness of the floor. An unflat floor is bumpy and wavy.

FF is measured over two 300mm slopes.

LEVELNESS (FL)

Relates to the tilt or slope of the slab. An unlevel floor is sloped or tilted. FL is measured over 3 meter spacing.

Ideally a floor should be constructed bothFL T and LEVEL.


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Floor Flatness Levelness


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Flatness & Levelness

Most users find that Flatness is more

important than Levelness.

Flatness comes from finishing tools and

techniques used, and from the concrete mix.

Levelness comes from formwork and strikeofftechnique and tools used.


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2 Types of FloorsRandom & Defined

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Random Traffic Floors~99% of all floors are Random Traffic

Traffic patterns can go anywhere on thefloor, in any direction.

Examples: Hotel Lobbies & Hotel Sleeping Rooms

Open Warehouses Office Space Factories & Assembly Plants Stores


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2 Types of FloorsRandom & Defined

Defined Traffic Floors

Only ~1% of all floors are Defined Traffic

Traffic patterns must always follow the exactsame path.

MHE is wire-or-rail guided Think of Railway Tracks

Older Defined Traffic Floors will show the path wear marks, skid marks on the floor

Example: High-Bay Narrow Aisle Warehouses


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2 Types of Floors

require 2 different types of specs

Random Traffic Floors: FF and FL (The F-Number System)

Gap under the Straightedge type specs

TR-34 Free Movement

Defined Traffic Floors: Fmin (Part of the F-Number System)

TR-34 Defined Movement

We will talk about specs for both types of floors

We will talk about all 3 tolerance methods


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Random Traffic Floors

The F-Number System FF FL

The F-Number System was invented byFace Construction Technologies, Inc.

FF Measures Flatness

FL Measures Levelness(Local Levelness) ACI (American Concrete Institute International)recommends the use of the F-Number system

How to measure Flatness?

Change in slope over a short distance If no change in slope, the floor is Flat. If slope changes a little, the floor is nearly flat. If slope changes a lot, the floor is not flat at all. A floor can be flat without being level


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F-Numbers

FlatnessBumpiness

FF

Levelness

Tilt

FL

F-Numbers are linear.An FF 40 is twice as flat as an FF 20 & half as flat as FF 80.

Most people agree that Flatness is much more important

than Levelness

Levelness is generally specified ~2/3 to 3/4 of Flatness

Flatness is almost always specified higher than Levelness


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The Change in Slope

is a Measure of Flatness

Not very FlatLow FF Number (FF 17) To get an acceptable floor, the bumps may need to be ground


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The Change in Slope


Medium-High Flatness (FF 47)


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The Change in Slope


Very FlatHigh FF Number (FF 94)


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The Change in Slope


3 profiles comparedFF 17, 47, 94


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Many measurements are collected

to calculate FF (Flatness)

Data are collected in straight lines evenly spaced

over the floor in both directions

Must collect enough data to be statisticallysignificant

Software automatically calculates the change in

slope at every step

Software automatically calculates FF from the

raw data


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Difference in Elevation over 3 m spacing

is a Measure of Levelness


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Many measurements are collected

to calculate FL (Levelness)

Data are collected in straight lines evenly spaced

over the floor in both directions

Must collect enough data to be statisticallysignificant

Software automatically calculates the changes in

slope at every step

Software automatically calculates FL from the

raw data


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Typical Section (Pour)

F-Number Report

Job: NSWCML Surface: FREEZER

Combined Section Section: F3-----------------------------------------------------------------------------------------------

Measured FF: 72.93 Specified FF: 65 Min Local FF: 40

Measured FL: 54.69 Specified FL: 50 Min Local FL: 3018 percent exceeds minimum local FF of 40.

28 percent exceeds minimum local FL of 30.---------------------------------------------------------------------------------------------------------

Run Name FF FL Readings

EW1 75.53 47.17 55

WE2 69.80 65.24 55

NS3 97.13 69.58 55

SN4 61.36 47.35 55

---------------------------------------------------------------------------------------------------------184 Z-Readings 220 Dipstick Readings


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AJB Group

Fillo Drive

Summerton

Project Summary Job Name: Fillo Drive

Surface: warehouse SOG

------------------------------------------------------------------------------------------------------------------

Measured FF: 86.26 Specified FF: 35.00 Min Local FF: 35.00

Measured FL: 63.25 Specified FL: 25.00 Min Local FL: 25.00

41 percent exceeds specified FF of 35.

42 percent exceeds specified FL of 25.

------------------------------------------------------------------------------------------------------------------

Total area of surface: 19200

Area measured: 5439

------------------------------------------------------------------------------------------------------------------Section Name FF FL Size

POUR1 90.46 83.52 663

POUR4 116.11 75.68 927

POUR9 148.55 100.97 668

POUR15 77.25 60.62 678

POUR17 63.94 57.59 941

POUR22 51.45 31.16 893

POUR25 65.50 41.70 668

Typical Project Summary (Overall)

F-Number Report


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TR-34 does not discriminate well

between good floors and bad floors

Almost everyone who has used both TR-34 &

F-Numbers prefers F-Numbers


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Only 3 choices are possible for Free Movement Floors

TR-34 Free Movement Specs

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Note that TR-34 always overemphasizes Levelness

and underemphasizes Flatness



TR-34 Overemphasizes Levelness

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TR-34 Free Movement Limitations

Only 4 Spec choices are available

All 4 Spec choices are relatively low (No High Tolerance Available)

Far too much emphasis on Levelnessnot enough on

Flatness

Not enough statistical data collected for Levelness

In the past, collecting Levelness data required a 2nd(different) instrument and two people

Can collect data for TR-34 with Dipstick

Still takes longer than F-Numbers to collect data




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Gap under Straightedge


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Straightedge Limitations

Straightedge test does not measure the utility of

the floor Only measures amplitude of flaws

Does not measure wavelength or frequency

Does not measure Levelness at all

The most common Straightedge Spec is 5 times

better than most floors Nobody can pass this spec

ACI recommends against using this spec try to avoid using Straightedge Specs

If you must use this spec, you can now collect

Straightedge data with Dipstick


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2 Methods of Measuring



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Measuring Defined Traffic Floors


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Fmin Report


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TR-34 Defined Movement Specs

Only 3 choices are possible for Defined Movement Floors

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Floor Profilers

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Many different profilers

are available

Not all of them produce the

same quality results!


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Data from 3rd

Party Test Lab- 10 test lines repeated on the same floor

Collected with their 6-year-old Swiveling Profiler

Note that all profiles are identical

Be careful to choose a quality profiler

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Rolling Profiler Data from 3rdParty Test Lab - 10 test lines on the

same line on the same floor Collected with their new model Rolling Profilerthe most expensive

profiler available

Which profile is the correct one?

Each profile is different, & F-Numbers are all different


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Data from Face Company - 10 test lines on the same floor

Collected with 8-year-old Swiveling Profiler Different Swiveling Profiler, different operator

Note that all profiles are identical


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Merged Data from 3rd

Party Test Lab & Face Company- 10 test lines on the same floor

Collected with 6 & 8-year-old Swiveling Profilers

2 Different Profilers, 2 different operators, same floor

Note that all profiles are still identical


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Closing Remarks

Choose a measuring system (Spec type) that

meets your needs.o Be careful to ensure that you specify a high enough flatness

o And dont overspecify levelness.

o ACI strongly recommends F-Numbers.

TR-34 has several limitations that detract

seriously from its utilityo Far too much emphasis on Levelness

o Not enough data for statistical significance

o

Too few spec choices

Gap Under the Straightedge specs just dont

work wello Dont use this system if you can use any other


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Closing Remarks

If you dont measure the floor, you wont know if

the floor meets your spec.

Use an instrument that is both precise and

accurate.o Poor quality instruments lead to disputes.

Measure and report results promptly to all

concerned parties.

Concrete floor companies can learn from theprofiles & F-Numberso They can improve their floors based on the data and profiles

from the instrument.


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References

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ACI 117o StandardSpecifications for Tolerances for Concrete Construction

ACI 302.1Ro

Guide for Concrete Floor and Slab Construction

ASTM E-1155o StandardTest Method for Measuring Flatness & Levelness of Floors

Technical Report # 34o

Guide to Design and Construction (The Concrete Society)

ACI 360o Guide to Design of Slabs on Ground

Specifications for Good Quality Concrete Floor - Tolerance REV J

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