CONCRETE SURFACE PREPARATION
Fred Goodwin
Fellow Scientist
BASF Construction Chemicals
Beachwood, OH
Surface Preparation:
The MOST Important Factor for the Success of
Coating and Lining Installations
SSPC Definition:
“The method or combination of methods used
•to clean a concrete surface,
•remove loose and weak materials & contaminants,
•repair the surface, and
•roughen the surface to promote adhesion”
•SSPC SP13 “An acceptable prepared concrete surface should:
• be free of contaminants,
laitance, loosely adhering concrete, & dust,
•provide a sound, uniform substrate
•be suitable for the application of the protective
coating or lining system.”
What problem did
we inherit?
What is
“unusual” with
the material?
What are we
trying to
accomplish?
What does the “boss”
(owner) want??
What do we have to
work around?
From ICRI 310.2
What is Concrete?
A Picture is Worth a Thousand Words…
What is Concrete?
Proportions
1 cubic yard =
27 cubic feet=
0.765 cubic meter
VOLUME %
Air / Porosity ~1-7%
3 feet
Water~ 12-16%
Cement ~ 10-15%
Fine Aggregate
- Sand ~30-80%
Coarse Aggregate
- Stone ~0-50%
3 feet
3 feet
Concrete Mix Rules of Thumb
• Cement
– as cement content, strength , shrinkage , cost 
• Sand
– as sand content
, workability , finishability , shrinkage 
• Stone
– as stone content
, workability , finishability , shrinkage 
• Water or water to cement (w/c) ratio
– as water
, workability , shrinkage  strength , durability 
• Air content
– as air content
, strength , bleed , freeze/thaw resistance 
Concrete Additives & Admixtures
MINERAL
ADMIXTURES
RETARDER
ANTI-BLEED
PLASTIC
EXPANSION
DEFOAMER
AIR
ENTRAINMENT
BINDER
Cement
SHRINKAGE
REDUCING
SHRINKAGE
COMPENSATION
DISPERSANT
ACCELERATOR
CORROSION
INHIBITOR
Design & Construction
Concrete
Kanare, H. Concrete Floors &
Moisture, Eng. Bulletin #119
PCA/NRMCA, 2005
From SSPC SP13
Concrete Cracks!
Plastic
Shrinkage
Thermal
Properties
PHASE 1
Drying Shrinkage
CRACKING
Contaminant Ingress
(oil, acids, nitrates,
etc.)
Carbonation
Chloride
Ingress
Reinforcement
Corrosion
Reinforcement
Corrosion
Moisture
Ingress
AAR
Oxygen
Diffusion
Reinforcemen
t Corrosion
Sulfate
Attack
Freeze/Thaw
Deterioration
Reinforceme
nt Corrosion
Further CRACKING, SPALLING, DELAMINATION, DINTEGRATON
PHASE 2
PHASE 3
H 2O
Thermal Cracking
Drying Shrinkage:
Higher Water to Cement Ratios Shrink More
ACI 224 R-01
Drying Shrinkage:
Lower Aggregate Contents Shrink More
At ALL Water to Cement Ratios
ACI 224 R-01
Drying Shrinkage:
Thinner sections dry (and shrink) faster
% of Ultimate Shrinkage
2” Thick
Slab
8” Thick
Slab
12” Thick
Slab
Time (0--------------------------24 Months)
Drying Shrinkage Cracking:
ASTM C1581 Cracking Potential
Steel Ring &
Strain Gauges
Inner and
Outer Steel
Ring for Mold
Cast Repair
Donut
Strip off Outer
Steel Ring
Wax Top Surface
Shrinkage Happens
Compresses Steel Ring
Steel Ring Resists
Specimen Cracks
Reinforcement Corrosion
Rusting (Oxidation) and deterioration of steel in concrete
which results in rust stains and/or disruption of the concrete
What do all of these have in common?
Two Types
• Natural WATER Sources • Artificial WATER Sources
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Weather
Water Table
Hydrostatic Pressure
Osmosis
Subslab Vapor
Indoor RH
Dew Point
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Mix Water
Curing Water
Leakage/Spills
Cleaning
Surface Preparation
Construction
Methods to
Minimize
NATURAL Water
Ingress
Kanare, H. Concrete Floors &
Moisture, Eng. Bulletin #119
PCA/NRMCA, 2005
Drying of Slabs
Drying from one side
4” Slabs to MVTR = 3 Lb/1000 sq. ft.
Bottom side moist
Higher W/C dries
slower.
Drying from both sides
external
humidity
If bottom ofNoslab
is wet,
harder to
dry.
Kanare, H. Concrete Floors & Moisture, Eng. Bulletin #119 PCA/NRMCA, 2005
Surface Preparation Method
Mechanics of Removal
ICRI 0310.2 Guideline for Selecting and Specifying
Concrete Surface Preparation
for Sealers, Coatings, and Polymer Overlays
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Erosion
Impact
Pulverization
Pressure
Solvation
Reaction
Expansive Pressure
Mechanics of Removal
Objectives
–Not Damage Structure
–Not Damage Reinforcing Steel
–Not Damage Surface To Be Coated
–Achieve Satisfactory Surface
Mechanics of Removal
ICRI 0310.2 Guideline for Selecting and Specifying
Concrete Surface Preparation
for Sealers, Coatings, and Polymer Overlays
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Mechanism of Method
Limits of Method
Surface Texture & Pattern
CSP Profiles
Problems & Issues with Method
Prepared Surface Result
Speed of Surface Preparation Range
How to QC Surface
Surface Preparation Methods
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Detergent Scrubbing
Low Pressure H2O
Acid Etching
Grinding
Sand/Abrasive Blasting
Shot Blasting
Scarifying
Needle Scaling
Hydrodemolition/High/Ultrahigh H2O Pressure
Scabbling
Liquid Surface Etchant
Flame Blasting
RotoMilling
Surface Preparation Methods
From ICRI 310.2
Surface Preparation Methods
Surface Preparation Methods
From ICRI 03732
Removal Methods
• Detergent Scrubbing
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Method: Solvation, Reaction
Limits: Soluble/Emulsifiable Contaminants
Surface Texture: No Improvement
Profile: ICRI CSP 1
Problems: Solution Disposal
Result: Wet Substrate
Production: 50-5000 sq m/hr (Mop→Large Riding Scrubber)
QC: Compare to Hand Scrubbed, Water Beading, Slip Tester
Surface Preparation Methods
• Low Pressure Water Cleaning
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Method: Solvation, Erosion
Limits: Soluble/Emulsifiable Contaminants and Loose Debris
Surface Texture: No Sound Concrete Removal, No Profile
Profile: ICRI CSP 1
Problems: Water & Loose Debris Disposal, Noise, Mist
Result: Wet Substrate
Production: 25-200 sq m/hr (hand held→quality of cleaning)
QC: Water beading, no loose material
Surface Preparation Methods
• Acid Etching
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Method: Reaction, Solvation
Materials: Muriatic (HCl), Sulfamic, Phosphoric, Citric
Limits: <10 mils Coatings
Surface Texture: Clean, Light Profile
Profile: ICRI CSP 1-3
Problems: Corrosive Solution, Rinse Water, Neutralization
Concrete >6 weeks old, Vacuum Removal
– Result: Wet Substrate
– Production: 150-750 sq m/hr
(hand scrubbing, vacuuming-medium scrubber)
– QC: Sandpaper type surface, pH
Surface Preparation Methods
Grinding
– Method: Erosion
– Limits: Coatings <6 mils,
Not for Sealers or Rubbery/Thermoplastic Coatings
– Surface Texture: Smooth, Dusty
– Profile: ICRI CSP 1-3
– Problems: Dusty, Noisy, Pattern & Edge Problems,
Media Replacement Cost
– Result: Leaves Dry, Dusty Substrate,
– Production: 2-75 sq m/hr (hand held-walk behind)
– QC: Visual Profile, Dust?
Surface Preparation Methods
Abrasive (Sand) Blasting
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Method: Pulverization, Erosion
Limits: Resilient Coatings, Dusty Or Wet/Vacuum (expensive)
Versatile: Sealers to 5mm Toppings
Surface Texture: Dry, Dusty Substrate, Media & Debris Disposal,
Profile: ICRI CSP 2-4
Problems: Compressed Air, Dust Control, Large Volume of Media
Result: Dry Dusty Surface
Production: 100-600 sq m/hr (soft concrete/equipment)
QC: Visual Profile, Dust & Contaminant Removal Verification
Surface Preparation Methods
Shot Blasting
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Method: Pulverization, Impact, Erosion 1-5 mm removal
Limits: Resilient Coatings, Sticky, Metallic, Saturants
Surface Texture: Striping, Pebbled, Sl. Exposed Aggregate
Profile: ICRI CSP 2-8
Requirements: Magnetic Broom, Electric/Propane/Diesel/Gasoline
Problems: Noisy, Striping Pattern, Edge Effects,
Maintenance, Powder Disposal, Vacuum, Shot Size & Usage
– Result: Leaves Dry, Non-dusty Substrate,
– Production: 14-420 sq m/hr (equipment, profile)
– QC: Visual Profile, Contaminant Removal Verification
Surface Preparation Methods
Scarifying
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Method: Impact 1-20 mm Removal
Limits: Not for <15 mil coatings, Elastomeric, Only Horiz.
Surface Texture: Striated Pattern, Multiple Passes
Profile: ICRI CSP4-9
Requirements: Power, Spare Parts, Vacuum Cleaner
Problems: Bruising, Dusty, Maintenance, Edge Effects, Noisy,
Debris Removal, Vibration
– Result: Dry Substrate, 0.1-1cm/pass, Dust + Granular Debris
– Production: 2-75 sq m/hr (hand held-walk behind)
– QC: Visual Profile, Contaminant Removal, Bruising Verification
Bruising Induced Bond
Failure
Surface Preparation Methods
• Needle Scaling
– Method: Impact, 1/2-2mm Removal, Edge Detailing,
Vertical, Horizontal, Overhead
– Limits: For <15 mil coatings, Elastomeric
Bruising?, Brittle Removal
– Surface Texture: Striated Pattern, Multiple Passes
– Profile: ICRI CSP 4-9
– Requirements: Compressed Air, Vacuum, Replacement Rods
– Problems: Dusty, Maintenance, Vibration
– Result: Leaves Dry Substrate, Dust + Granular Debris
– Production: 1-5 sq m/hr (hand held)
– QC: Visual Profile, Contaminant Removal, Bruising?
Surface Preparation Methods
• High & Ultra High Pressure Water Jetting, Hydrodemolition
– Method: Erosion, Expansive Pressure,
10-150 mm Removal, Horizontal & Vertical, Robots
– Limits: Water Disposal, Mist, Noise, Removal Based on Soundness
– Surface Texture: Variable Depending on Substrate, Equipment
– Profile: ICRI CSP 6-9
– Requirements: Water, Debris Collection, Special Equipment
– Problems: Maintenance, Messy, Vibration,
High Pressure, Runoff Protection, Mist, Spray
– Result: Leaves Wet Substrate, Runoff, Debris
– Production: 12-28 sq m/hr, Variable on Equipment & Substrate
– QC: Visual Profile, Water Beading, Contaminant Removal
High Pressure Water - 15,000 40,000-psi, Water Jet Velocity up to 1,500 mph
Flow Rate - 7 – 100 gpm
Controlled by size and number of parallel pumps
(Rampart uses 35,000psi)
Nozzle Rotation
0 – 1,800 rpm
Adjustable in field
Angled Nozzle
0 – 30 degrees
Changeable in field
Hydrodemolition
Stand Off
Equipment setting
Surface Preparation Methods
Scabbling (Bush Hammer)
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Method: Impact, 2-20 mm Horizontal, Light Duty Vertical
Limits: Frequent Bruising, Not for Elastomeric or Gummy
Surface Texture: Irregular Pattern w/Fractured Aggregate
Profile: ICRI CSP 7-9
Requirements: Air or Hydraulic Powered, Low Maintenance
Problems: Dusty, Noisy, Moderate to Severe Vibration,
Sweeping & Vacuuming
– Result: Dry/Dusty/Fractured Substrate, Debris <12mm
– Production: 2-9 sq m/hr (hand held-walk behind)
– QC: Visual Profile, Contaminant Removal
Bruising (Eliminate w/Sand-, Steel-, or H2O-Blast)
Flame Blasting
– Method: Expansive Pressure, Reaction,
2-12 mm Horizontal, Vertical, & Overhead, Portable,
Good for Coatings, Elastomeric, Saturants, Gummy
– Limits: H2O Presaturate, Open Flame, Toxic Fumes, Hot Flying Chips
– Surface Texture: Dust Free, Irregular Chipped Surface, No Pattern
– Profile: ICRI CSP >8
– Requirements: Ventilation, Oxygen/Acetylene, Special Equipment
– Problems: Hot Flying Debris, Fumes, Bruising?
– Result: Dry Chipped Surface with Hot Charred Debris
Remove by Sweeping or Air
– Production: 5-55 sq m/hr (hand held-walk behind)
– QC: Visual Profile, Eliminate Bruising (Sand Blast Follow up)
Contaminant Removal
ACETYLENE
OXYGEN
• RotoMilling
– Method: Impact, Horizontal 4-100mm depth,
– Limits: Bruising, Edge & Corner Effects, Straight Path,
Clearance, Overlapping Passes, Large Volume Debris
– Surface Texture: Deep Profile, Striated or Grooved Pattern,
Fractured Aggregate
– ICRI CSP: 9
– Requirements: Support of Heavy Equipment, Special Equipment
– Problems: Bruising, Clearance, Heavy, Large Areas, Dust, Noise,
Vibration, Removal of Large Volume of Debris
– Result: Very Rough, Chipped Surface, Grooves
– Production: 9-1400 sq m/hr (size of machine)
– QC: Visual Profile, Contaminant Removal,
Eliminate Bruising (Sand, Steel, or H2O Blast Follow up)
• Liquid Surface Etchant
– Method: Reaction
– Limits: Fresh Concrete Only, Timing, Debris Removal,
Wet&Green Substrate
– Surface Texture: Deep to Shallow Profile, No Pattern,
Exposed Aggregate
– ICRI CSP: 3-9
– Requirements: Apply During Concrete Placement,
Poly Film Cure, Water Blast Off
– Problems: Removal of Large Volume of Debris, Timing,
Wet & Green Substrate, Return for Removal
– Result: Controlled depth of etch by:
• Etchant type,
• Cure rate,
• Timing or Removal
– Production: 5-100 sq m/hr
– QC: Visual Profile, Debris Removal,
(H2O Blast Follow up)
Performance tests for concrete following surface preparation from SSPC SP 13.
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Bond/Tensile Adhesion/Bruising Test
Bruising
?
?
Overlay Tensile
Concrete
Failure
Repair Bond
Failure
Adhesive
Failure
Topping
Compound
?
Substrate Failure
Adhesive
Failure ?
ICRI 210.3
ASTM C1583
Bond Test
Appearance
Water Beading
Water Wetting
pH of Surface
Phenolphthalein
in ~70% Alcohol
pH of Wash Water
Compressive
Strength
Things to Know:
Cylinders vs Cubes
Cored/Cut vs. Cast
Break ~15% to 20%
lower
Defects Increase
Variance & Decrease
Strength
Hard to Cheat
Curing
Wet Burlap
Poly Film
Curing Compound
Curing Induced Strength Variations
TESTING Water Vapor Permeability
General
Guidance
ASTM E 1907
ACI 302.2 R-06
ASTM D 4263
ASTM F 1869
ASTM F 2170
Over Granular Fill
Vapor Barrier Present
Under Granular Fill
On Grade
Horizontal
No Vapor Barrier
Orientation
Suspended
Vertical
Overhead
From Concrete Placement (Fresh / Green Concrete)
From Cleaning / Process
From Surface Preparation
Positive Hydrostatic
Moisture
From Hydrostatic Pressure
Negative Hydrostatic
Moisture Vapor Emission
From Substrate
Drainage
Form Release
Curing Compound / Existing Membrane
Oil
Early / Dusting / Laitence
Contamination
Carbonation
Late
Chlorides
Other Chemicals
Interior
Substrate
Conditions
Substrate Conditions
Other Chemicals
Interior
Exterior
Exposure
Primary
Chemical Containment
Secondary
Elevated
Freezing
Temperature
Ambient
Differential
Formed
Wood Float
Metal Trowel
Power Trowel
Broom Finish Finish
Sacking
Stoning
Concrete Quality
Block
Shotcrete
Porosity
Strength
Dynamic
Extent of Cracking
Static
Substrate Conditions
low pressure water
Cleaning
detergent scrubbing
Grinding
Abrasive Blasting Erosion
Shotblasting
Bush Hammers
Scabblers Impact
Needle Scaling
Scarifiers Pulverization
Surface Retarder Application
Acid Etchning
Chemical Reaction
Priming?
Emulsification
Hydrodemolition
Expansive Pressure
Flame Scarification
Surface Preparation Mechanism
Wet Substrate OK
Moisture Dry Substrate Needed
Moisture Vapor Emission Problems
Tensile Strength
Sealers 0-3 mils/ 0-75 microns CSP 1-2 1/2
Thin Film Coatings 4-10 mils / 100-250 microns CSP 1-3
Coating Requirements
High Build Coatings 10 mils - 40 mils 250 - 1000 microns CSP 2-5
Profile
Self Leveling 50 mils - 1/8" 1250 microns - 3 mm CSP 3-6
Polymer Overlays 1/8 - 1/4" 3 - 6 mm CSP 4-9
Toppings >1/4" >6mm CSP 4-9
pH
Surface Cleanliness (Dust)
Duration
Working Window
Ambient
Temperature
Conditioned
Electricity
Water
Utility Supply Ventilation
Compressed Air
Light
Noise
Application Conditions
Vibration
Fumes
Environmental Impact
Debris Disposal
Hazardous Waste
Surrounding Area
Height
Weight
Physical Constraints Access
Width/Turning Radius
Area
Time
Abrasion Resistance
Chemical Resistance
Aesthetics
Thickness Tolerance
Owner Requirements
Slip Resistance
Time Constraints
Environmental Impact
Cost
BASF Construction Chemicals
Fred Goodwin
Fellow Scientist
?
Over Granular Fill
Under Granular Fill
Vapor Barrier Present
On Grade
Horizontal
No Vapor Barrier
Orientation
Suspended
Vertical
Overhead
Wet Substrate OK
From Concrete Placement (Fresh / Green Concrete)
Moisture
From Cleaning / Process
Moisture Vapor Emission Problems
From Surface Preparation
Tensile Strength
Moisture
Positive Hydrostatic
From Hydrostatic Pressure
Negative Hydrostatic
Moisture Vapor Emission
Sealers 0-3 mils/ 0-75 microns CSP 1-2 1/2
Thin Film Coatings 4-10 mils / 100-250 microns CSP 1-3
From Substrate
Drainage
Coating Requirements
High Build Coatings 10 mils - 40 mils 250 - 1000 microns CSP 2-5
Profile
Form Release
Curing Compound / Existing Membrane
Toppings >1/4" >6mm CSP 4-9
Contamination
Carbonation
Late
Self Leveling 50 mils - 1/8" 1250 microns - 3 mm CSP 3-6
Polymer Overlays 1/8 - 1/4" 3 - 6 mm CSP 4-9
Oil
Early / Dusting / Laitence
Dry Substrate Needed
pH
Surface Cleanliness (Dust)
Chlorides
Other Chemicals
Substrate Conditions
Interior
Exterior
Primary
Duration
Time
Exposure
Secondary
Working Window
Ambient
Chemical Containment
Temperature
Elevated
Conditioned
Electricity
Freezing
Temperature
Ambient
Water
Utility Supply
Differential
Ventilation
Compressed Air
Formed
Light
Surface Preparation Selection
Wood Float
Metal Trowel
Noise
Application Conditions
Power Trowel
Vibration
Finish
Broom Finish
Fumes
Sacking
Environmental Impact
Stoning
Concrete Quality
Block
Debris Disposal
Hazardous Waste
Shotcrete
Surrounding Area
Porosity
Height
Strength
Weight
Dynamic
Extent of Cracking
Static
Physical Constraints
Access
Width/Turning Radius
low pressure water
Area
Cleaning
detergent scrubbing
Grinding
Abrasive Blasting
Abrasion Resistance
Erosion
Chemical Resistance
Shotblasting
Aesthetics
Bush Hammers
Scabblers
BRUISING
Scarifiers
Pulverization
Surface Retarder Application
Chemical Reaction
Emulsification
Hydrodemolition
Flame Scarification
Surface Preparation Mechanism
Thickness Tolerance
Slip Resistance
Time Constraints
Environmental Impact
Cost
Acid Etchning
Priming?
Owner Requirements
Impact
Needle Scaling
Expansive Pressure