A Look at Reactive Resin Chemistries: Bonding Agents, Structural Anchoring Adhesives, and Repair...
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Transcript of A Look at Reactive Resin Chemistries: Bonding Agents, Structural Anchoring Adhesives, and Repair...
A Look at Reactive Resin Chemistries:
Bonding Agents, Structural Anchoring Adhesives and Polymer
Repair Mortars
Growing in Use Everyday
Chemistries
Properties / Specification
Applications
CHEMISTRIES
Type of Chemistries
• Concrete & Mortars
Cementitious - Hydraulic Crystalline Hardening
• Epoxies, Polyureas, Urethanes, Polysulphides
Stoichiometric
• Polyesters, Vinyl Esters & Acrylics
Free Radical
Overview of Chemistries• Cementitious
– Cement + Water (+aggregates)• Epoxy
– Diglycidyl Ether of Bisphenol A + Amine Hardener• Polyurea
– Reactive Isocyanate + Amine Hardener• Polyurethane
– Reactive Isocyanate + Polyol (+Catalyst)• Polyesters & Acrylics (Methacrylates)
– Polyester (& Styrene) or Reactive Acrylic + Catalyst and Peroxide
They All Have In Common:THERMO-SETTING =
HEAT DRIVEN REACTIONS
Non-Reversible
REACTION PROCESS
Polymer
Resin
Cement
Hardener
Catalysts
Water
Mix A with BWorking
TimeGel
Time Hardens Solid
HEAT DRIVEN
ReactionInitiates
ReactionStabilizes
A
B
Cure Time Diagram
What Governs Heat?
• Ambient Temperature• Substrate Temperature• Material Temperature• Sunlight (Seasonal/Location Dependent)• Bulk Mass• Wind• Temperature Rising or Dropping?
Cementitious: The chemical reaction starts a crystal-type growth in the
cement
Epoxies
• Two Part Products– Part A (Epoxy) + Part B (Hardener) = Adhesive
• Defined Mix Ratio• Thermo-setting - Temperature Sensitive
– Heat Driven & Mass Driven• Inherently Strong Bond To Concrete, Wood,
Metals, Mortars & Many Rock Types
Epoxies
• Thermosetting• Temperature Dependent• Epoxy & Amine• Shrinks upon cure• Inherently Strong Bond to Concrete, Mortars,
Metals and Wood• Stoichiometric Mix Ratio
– Predetermined or Required Mix Ratio
Epoxy Technologies
• Epoxies– Bis, A– Bis, F– Novalac
Epoxy Technologies
• Amines– Polyamides (good flexibility, poor properties)– Amidoamines (very poor low temp cure, excellent
bond)– Aliphatic (very good cure at low temps, poor
bond) – Cycloaliphatic (good cure at low temps and moist
conditions, good bond)
Stoichiometric Reaction
• Requires a predetermined amount of Amine to react with a known amount of Epoxy.
• Typically…100 Parts of Epoxy to 50 Parts of Amine
• Mixing – Number one cause of Problems
Pot-life of Epoxies (working time)
• Pot Life – The time at which 60gms of combined Epoxy/Hardener Resins react to become a hardened gel.
• Typically, every 150F rise in temperature cuts pot-life in half.
• Typically, every 150F drop in temperature doubles pot-life.
Thin Film Set Time
• EPOXY–Thin film set time (20 mils) is 10- 15
times the pot life.• Polyester
–Thin film set time (20 mils) is 5-10 times the pot life.
Benefits, Epoxies
• Bond Tenaciously to Concrete– Inherent affinity to bond to polar substrates
• Forgiving– 15% off on mix ratio
• Resilient• Volumetrically Stable
– Does not shrink after initial cure
Benefits, Epoxies. Contd.
• Highest Mechanical Properties of all typical resin systems – 3-5 times greater
• Very High Dynamic Loading• High Modulus• Flexible• Chemical Resistance
Considerations
• UV Stability– Turns Yellowish
• Low Thermal Capacity– Tg of 1300F-1400F
• High Coefficient of Thermal Expansion• High affinity to water.
Polyesters – Vinyl Esters
• Thermo-Setting Resin• Free-Radical Reaction
• Unsaturated Polyester Resin & Styrene
• Heat Dependent• Forgiving Mix Ratio• Shrinks After Cure (Avg. 15%)
Polyesters – Vinyl Esters
• Most reliable cure due to low mix ratio sensitivity.• Moisture insensitive when cured.• Easy to use in a wide range of temperatures.• No heating of cartridge required.• Ideal for high/low temperatures.• Low Mechanical Properties – 3-5 times lower than
epoxies.
Chemistries
Properties / Specification
Applications
Physical PropertiesCompressive Strength
The surface area equal to a 8.5”x11” sheet of paper of a material having 10,500 psi compressive strength will support
1 MILLION LBS. of Dead Load
Cementitious: Low-High Resin: Low-High
Physical PropertiesHardness and Abrasion
Air
70D
80D
98D
Aggregate
Cured ResinCement Paste
94D
Greater the Hardness, the better abrasion resistance
Physical Properties
Tensile Strength
Cementitious: Low Resin: High
Physical Properties
Flexural Strength
Cementitious: Low Resin: High
Bond StrengthDefines the strength at which a material will shear or pull from the substrate at the interface.
Shear Bond Tensile Bond
CEMENTITIOUS: HIGHRESIN: HIGH
Bonding Characteristics
Repair Material
Concrete Substrate
Cementitious – Mechanical Bonding• Cleaned & Opened Pore Structure• Roughened to Increase Surface Area• Pre-dampen
Resins – Chemical & Mechanical Bonding• Cleaned & Opened Pore Structure• Roughened to Increase Surface Area
Bond Strength is the last and slowest to develop. Once compromised, will not regain strength.
Physical Properties
Coefficient of Thermal Expansion
T1
T2 (Concrete)T
L
T2 (Resin)
Thermal CompatibilityCoefficient of Thermal Expansion (in./in.0F)
• Concrete – 0.000008• Concrete Structures – 0.0000055• Epoxy – 0.000310 (4-6 times greater) • Polyester / Vinyl Ester – 0.000069 (8-14 times
greater)• Acrylic – 0.000130 (16- 26 times greater)
Modulus of Elasticity
Measures the stiffness of a material. The lower the modulus
the greater the deformation under a given load. The lower the modulus, the greater the
coefficient of thermal expansion.
Young’s Modulus of Elasticity
• Concrete– Modulus of Elasticity 3,700,000 to 4,500,000 PSI
• Resin Based Materials– Modulus of Elasticity 250,000 to 700,000 psi
Factor of 6 – 18 Times Greater
Thermally Induced Stress = Young’s Modulus of Elasticity
* Coefficient of Thermal Expansion
* Thermal Variance
Factor of 24 – 108 for a Neat Epoxy
Cementitious
•Slow – Fast Setting•Variable Mix Ratio•Strong Bond to self•One-dimensional Physical Properties•Moderate Shrinkage•Very High Modulus•Very Low Thermal Expansion Coefficient
Epoxy•Slow - Fast Setting•Moisture Insensitive•Critical Mix Ratio•Inherently Strong Bond•Nominal Shrinkage•High Physical Properties•Low - Moderate Modulus•High Thermal Expansion Coefficient
Polyurea•Very Rapid Setting•Moisture Sensitive•Critical Mix Ratio•May Have Poor Bond•Low- Moderate Strength•Nominal Shrinkage•Low - Moderate Modulus•High Thermal Expansion Coefficient
Polyesters Acrylics
•Very Rapid Setting•Moisture Tolerant•Non-critical Mix Ratio•Good Bond•Moderate - High Shrinkage•High Physical Properties•Moderate Modulus•High Thermal Expansion Coefficient
Resin-Based Repair Materials
• Preclude the use of Resin Based Mortars under conditions of frequent or large temperature fluctuations.
• When the cause of concrete failure was reinforcing steel corrosion. Because, the different electric properties of the resin mortar vs. the concrete will set-up an incipient anode effect.
Governing Specification ASTM C 881
• Categorized into Three Groupings– Usage “Type” – Load Bearing / Non-Load Bearing
• Seven Types
– Viscosity “Grade” – Low “1”, Medium “2” and Gel “3”
– Application Temperature “Class”• Six Classes, “A” Below 45F; “B” 45F-65F; “C” 65F+“D” Below 45F; “E” 45F-65F; “F” 65F+ (Type VI & VII)
ASTM C 881 ClassificationsASTM C 881 CLASSIFICATIONS
Type I
Type II
Type III
Type IV
Type V
Type VI
Type VII
Grade
Class A For use below 40°F (4°C) the lowest allowable temperature to be defined by the manufacturer of the product
B For use below 40°F and 60°F (4 and 16 °C),
For bonding and sealing segmental precast elements with internal tendons and for span-by-span erection when temporary post tensioning is applied.For use as a nonstress carrying sealer for segmental precast elements when temporary post tensioning is not applied as in span-by-span erection.
C For use above 60°F (16°C) the highest allowable temperature to be defined by the manufacturer of the product.
1 Low Viscosity 2 Medium Viscosity3 Non-Sagging
Consistency
For use in non-load bearing applications for bonding hardened concrete to hardened concrete and other materials, and as a binder in epoxy mortars or epoxy concrete.
For use in non-load bearing applications for bonding freshly mixed concrete to hardened concrete.
For use in bonding skid-resistant materials to hardened concrete, and as a binder in epoxy mortars or epoxy concretes used in traffic bearing surfaces (or subject to thermal or mechanical movements).For use in load bearing applications for bonding hardened concrete to hardened concrete and other materials and as a binder for epoxy mortars and concretes.
For use in load bearing applications for bonding freshly mixed concrete to hardened concrete.
ICC ER vs. ES REPORTS• ICC ER- Legacy Report (AC-58)• ICC mandated that ER reports are outdated• ICC drafts Building codes such IBC, IECC, IEBC and
many more. State dependent.• ICC is an independent Business (non-governmental)• ICC ES Legacy Report (AC-308) • Fully Comply to AC-308
– Cracked and Uncracked Concrete
ICC ES Reports
• DOT’s have not welcomed AC 308 or AC 58– Except for Caltrans and Utah
• ACI is always adopted as building code.• ACI drafted ACI 318 which requires AC 308
Conformance. Building Codes are not relate to pavements / bridges.
• ACI 318 requires that contractors that install anchors specified under ICC (ES AC 308) must be independently certified (by ACI).
Non-Structural
• Dispersions or Emulsions• Conforms to ASTM C 1059 Type I or II
Dispersions are Classified by:
• ASTM C 1059 TYPES• Type I is Non-Reemuslifiable
– Must be used as a Slurry Coat– Can not be allowed to dry– Minimum Slant Shear Bond Strength 1,000 psi
• Type II is Reemusifiable– Can be used neat– May be allowed to dry– Minimum Slant Shear Bond Strength 500 psi
Dispersions
• Thermo-Plastic• Must Coalesce
– Minimum Film Forming Temperature– Glass Transition Temperature
• Must be used in a film or mix with cementitious material
• Bond Enhancifiers
Chemistries
Properties / Specifications
Markets / Applications
Markets
• Anchoring/Fasteners• Adhesives / Glues
Anchoring Market
• Cast In Place• Post-Installed
Post Installed Market
• Mechanical Anchors• Bonded Anchors (Chemical Adhesives)• Grouted Anchors (Cementitious)• Forced Entry Anchors (Pneumatic)
Mechanical Anchors
• Static Load• Ambient Temperature Applications• Poor exterior Performance – Corrosion• Easy to Use• Very Common
Bonded Anchors
• Static and Dynamic Loads• Ambient Temperature Applications• Versatile• Good Exterior Performance• Good Chemical Resistance
Grouted Anchors
• Static Loads• High and Low Temperature Use• Good Exterior Performance• Good Chemical Resistance
– Except Acids
Forced Entry Anchors
• Static Loads• Ambient Temperature Use• May Damage Host Substrate• Edge and Corner Issues• Speed of Application Can be Very High
Applications
Chemical Adhesives - Bonded AnchorsBonding Agents
GENERAL CONSTRUCTION APPLICATIONS
• Rebar doweling into concrete• Anchoring threaded rod or rebar into brick,
block and stone.• Attaching steel angles or ledgers to brick or
block.• Attaching sill plates to concrete.• Stadium and auditorium seating.
GENERAL CONSTRUCTION (cont.) APPLICATIONS
• Quick-setting crack injection surface sealer• Injection resin to repair• Bonding concrete to concrete• Facade pinning• Concrete repairs and patching
HIGHWAY CONSTRUCTION APPLICATIONS
• Highway guard rails• Pavement highway reflectors• Railings and fences• Rebar doweling for highway widening and
repair projects• Light poles• Highway sign installations
BRIDGE CONSTRUCTION APPLICATIONS
• Rebar doweling into concrete• Highway lane ties• Concrete repairs/patching• Guard rails and fences• Pavement reflectors
PLANT MAINTENANCE
• Anchoring vibratory equipment and conveyors• Machinery anchoring• General plant maintenance• Anchoring in corrosive environments• Railings and fences• Supports and brackets for pipes• Floor repairs
RAILROAD CONSTRUCTION APPLICATIONS
• Support brackets for rail systems• Railroad concrete tie repairs• Third rail anchoring
PORT CONSTRUCTION APPLICATIONS
• Concrete dock repairs• Bridge pier reinforcement• Pier cap repairs• Mooring cleats• Underwater anchoring• Anchoring bumpers
CORRECTIONAL FACILITIES APPLICATIONS
• Pick-proof sealants for doors and windows• Pipe supports and brackets
General Grouting Applications for Non-Shrink Cementitious Materials
• Railings• Anchors• Anchor Bolts• Dowels• Reinforcing Steel• Threaded Rods• Machinery Bolts• Sign Post
• Parking Meters• Traffic Signs• Ties• Hooks• Ornamental Iron
Work
Anchors Summarized• Each Anchor Type has it place in the
Market.• Mechanical - Easy to Use…Static Load• Bonded – Dynamic Loading…Very High
Strength…Exterior Applications.• Grouted – Static Load…High Temperature…
Cheap• Forced Entry – Very Quick Installation…
Static Load or Temporary