APT Asphalt Substrate

Project CycleProject Cycle

Project

(1) SubstrateCharacteristics Consultants

Architect

Specification

Project

(1) SubstrateCharacteristics

(2) PerformanceRequirements

ConsultantsArchitect

Specification

DesignInnovation

Specification

Project

(1) SubstrateCharacteristics

(2) PerformanceRequirements

ConsultantsArchitect

MaterialSupplier

Specification

DesignInnovation

Specification

Material Innovation

Material Supply

Project

(1) SubstrateCharacteristics

(2) PerformanceRequirements

(3) Application

ConsultantsArchitect

MaterialSupplier

Contractor

Specification

DesignInnovation

Specification

Material Innovation

Material Supply

Installation

Project

(1) SubstrateCharacteristics

(2) PerformanceRequirements

(3) Application

(4) Verification

ConsultantsArchitect

MaterialSupplier

TestLaboratory

Contractor

Specification

DesignInnovation

Specification

Material Innovation

Material Supply

Installation

Project

(1) SubstrateCharacteristics

(2) PerformanceRequirements

(3) Application

(4) Verification

ConsultantsArchitect

MaterialSupplier

TestLaboratory

Contractor

ContractorManagement

Maintenance Specification

DesignInnovation

Specification

Material Innovation

Material Supply

Installation

Substrate CharacteristicsSubstrate Characteristics

1. Chemistry of Asphalt2. Physical Properties of Asphalt3. Asphalt Substrates4. Principles of Coating Technology

Terminology: Bitumen

Bitumen = amorphous substance:

• asphaltenes = dispersed phase

Chemical Structure of Ashaltenes

CH2

CH3

CH2

CH2CH2

CH2CH

CH2CH2

CH2CH2

CH2CH3

CH3

Terminology: Bitumen

Bitumen = amorphous substance:

• asphaltenes = dispersed phase• polar resin (protective layer)

“Asphaltic cement” = binder

• mixture of aromatic oils

Terminology: Asphalt

Asphalt partially crystalline mixture • Bitumen (polymer-modified)• Aggregate (rock)• Sand“Asphaltic Concrete”

Polymer Modifications• Epoxy Asphalt• Polyurethane Asphalt• Polysulfide Asphalt• Polyester Asphalt• Phenolic Asphalt• Rubber Asphalt• Thermoplastic Asphalt

Terminology: Asphalt Emulsions

Mixture produced in colloid mill:• Asphalt in water emulsion• Stabilized by anionic or cationic surfactantsUsed in subbase stabilization, cold patch compound, road oils

Substrate Characteristics (2)Substrate Characteristics (2)1.Chemistry of Asphalt2. Physical Properties of Asphalt3. Asphalt Substrates4. Principles of Coating Technology

Glass Transition Temperature Tg

Transition of amorphous Materialsfrom glass-like, hard-elasticto liquid, rubber-elastic

Based on freeze-thaw-cycle of Brown’s molecular movements

Rheological Behavior of Bitumen

Temperature

Visc

osity

Newtonian Liquid

Ideal Behavior

Modified Bitumen

-25°C to -15°CTg

50°C to 70°CViscoelastic to Newtonian

ServiceRange

ProcessRange

Rheological Nature of Asphalt

Newtonian fluidT > 70 °C

viscoelastic, thixotropic fluid- 10 °C < T < 50 °C

amorphous, glass-like materialT < - 20 °C

RheologyTemperatureT (in °C)

Dilutent Evaporation

0

10

20

30

40

50

60

70

80

90

100

1 day 1 week 1 month 4 month

% o

f Dilu

tent

Eva

pora

ted

Rapid CureMedium CureSlow Cure

Substrate Characteristics (3)Substrate Characteristics (3)1. Chemistry of Asphalt2. Physical Properties of Asphalt3. Asphalt Substrates4. Principles of Coating Technology

Asphalt Concrete Paving

Asphaltic Concrete (“Blacktop”):Mixture of polymer-modified asphalt(asphaltic cement), aggregate and sand• Penetration Grade (ASTM D 946)• Viscosity Grade (ASTM D 3381)

Installation

• Surface Preparation(compaction of subbase, prime coat)

• Placement of asphalt concrete mixture (spreading at a minimumtemperature of 105 °C/225 °F)

• Rolling (Compaction)

Field Quality ControlASTM F2157-02 - Standard Specificationfor Synthetic Surfaced Running Tracks

Section 5 -Test Methods and Requirementsfor Asphalt Base

5.1 Type and Compactiontwo layers: base and wearing course95% density (machine finished areas)90% density (hand packed areas)

5.2 Test Method ASTM D2950

Field Quality Control (2)ASTM F2157-02 - Standard Specificationfor Synthetic Surfaced Running Tracks

Section 5 -Test Methods and Requirementsfor Asphalt Base

5.3 Evenness3-m straight edge depression not to exceed

6 mm (Class A & B)8 mm (Class C)

Substrate Characteristics (4)Substrate Characteristics (4)1.Chemistry of Asphalt2. Physical Properties of Asphalt3. Asphalt Substrates4. Principles of Coating Technology

Polyurethane (PUR) Coating

• 1-component (1K) moisture curedPUR Prepolymer + water

• 2-component (2K) chemical curedDiisocyanate (NCO) or PUR-Prepolymerreacting with Polyol-component

1K PUR: Advantages and Application Limitations

– curing profile greatly dependent onclimate conditions

moisture leveltemperature

– no thick film applications

+ no second component required

1K PUR Prepolymer (Binder)

3939Moisture-cured prepolymerBinding of rubber granulesPaved to 10 mm thicknessCure time of 24 hours

Spurtan: Sandwich SystemTop layer poured-in place

EmbeddedEPDM granules

UV protection& durability

Paved in placePUR-bound rubber-base-mat

2K PUR: Advantages and Application Limitations

+ thin and thick-film applications+ curing profile independent of

moisture levels in environment

– mixing of A&B component at correct mixing ratio required

APT PU Mixing machine

APT 2K PUR MachineSpeed ControlVFD Pump A

Speed ControlVFD Pump B

Progressive Cavity Pump A Progressive Cavity Pump B

Mixing Tube

PUR A/B Output

from B-reservoirfrom A-reservoir

EMO-500Ratio Monitor

Flowmeter A Flowmeter B

2K PUR Coating

5050Chemical-cured coatingEmbedding of EPDMPot life 35 minutesCure time of 24 hours

Rekortan: Full-pour SystemTop layer poured-in place Embedded

EPDM granules

Automated Installation of2K PUR Coating

Multi-LayerMiddle:Shock Absorbingmicro-foam PURQualipur 5050SABottom:Leveling layer

ReferencesReferences[1] Usmani, A.M.; Asphalt Science and Technology. 1st

ed.;New York, NY: Marcel Dekker, Inc., 1997[2] HEWLETT, P. (Editor): Lea’s Chemistry of Cement and

Concrete, 4th ed., Burlington, MA: Elsevier, 2004[3] ASTM F2157-02: Standard Specification for Synthetic

Surfaced Running Tracks, West Conshohocken, PA: ASTM International 2002

[4] ASTM D946-99: Standard Specification for Penetration-Graded Asphalt Cement for Use in Pavement Construction, West Conshohocken, PA: ASTM International, 1999

[5] ASTM D3381-99: Standard Specification for Viscosity-Graded Asphalt Cement for Use in Pavement Construction, West Conshohocken, PA: ASTM International, 1999