Chapter 4 Chapter Topics Measuring floor flatness and levelness The 10 ft 3m straightedge method Fnumber system Factors affecting floor flatness and levelness Definitions Flatness Waviness or bumpiness of slab surface ID: 134984
Download Presentation The PPT/PDF document "Floor Flatness and Levelness" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Floor Flatness and Levelness
Chapter 4Slide2
Chapter Topics
Measuring floor flatness and levelness
The 10 ft (3m) straightedge method
F-number system
Factors affecting floor flatness and levelnessSlide3
Definitions
Flatness Waviness or bumpiness of slab surface
Smooth
Levelness
Tilt or slope of slab surfaceSlide4
Measuring Flatness and Levelness
Gap under a 10 ft straightedge
Oldest method
Measures only floor flatness; not levelness
Generally less satisfactory way of
measuring
F-number system
Measures floor flatness and levelness
Must be used if floor exceeds 10,000 sf (ACI 301)
Measurements in accordance with ASTM standardSlide5
The 10 ft Straightedge Method
Measured within 72 hoursPlace an unleveled 10 ft straightedge on slab
Rests on two high spots
Measure gap at any point under straightedge between two high spots
100% compliance with straightedge not realistic
Four out of five measurements more realisticSlide6Slide7Slide8
F-Number System
Measure within 72
hours
FF – floor flatness FL – floor
levelness
To get F-numbers
Measure surface elevations at 12 inches on-center
FF (bumpiness) calculated over 24 inch length
FL (tilt) calculated over 10 ft
length
F-number pair always written in order:
FF/FL
Higher F-numbers: the flatter and more levelSlide9
F-number System
Two different sets of F-numbers
Specified Overall Value (SOV)
Minimum Local Value (MLV
)
Check specifications for
requirements
ACI 302 provides
recommendations
Measure in accordance with ASTM E
1155
FL should not be measured on sloped slabsSlide10Slide11Slide12Slide13Slide14Slide15Slide16
Factors Affecting Flatness
Concrete workability, finishability, and setting time;The window of finishability
Sun, wind, rain, temperature extremes,
Amount of sunlight on the slab;
Timeliness of concrete delivery;
Uniformity of concrete slump, as delivered;
Consistency of final setting time; and
Site accessibility.Slide17
Factors Affecting Levelness
Accuracy of edge forms
Quality of initial
strikeoff
Wet screeds are harder to get higher
FL
Smaller strip placements are easier to get higher FLSlide18
End of Chapter 4