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PAVING ASPHALTS Origins, properties, manufacture and use

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Presentation on theme: "PAVING ASPHALTS Origins, properties, manufacture and use"— Presentation transcript:

1 PAVING ASPHALTS Origins, properties, manufacture and use
Dr. Ludo Zanzotto Bituminous Materials Chair Faculty of Engineering University of Calgary May 2001

2 Historical Background
One of the oldest engineering materials “asphaltos” - sticky, firm - Greek “jatu-krit - pitch creating - Latin: “pixtumen” Use: Sumerians (3000 B.C.) - building purposes Egyptians (2500 B.C.) - “mumyia” - mummy Biblical times ( B.C.) Noah’s ark - waterproofing Tower of Babel - mortar Paving

3 Sources and Manufacture of Asphalt
natural asphalt crude oil Asphalt manufacture distillation oxidation extraction modification cracking processes Paving asphalt represents 3 ~ 4 % of the total annual crude oil throughput in USA and Canada

4 Yield of Asphalt from Different Crude Oils
BOSCAN VENEZUELA 10.1 .999 6.4 ARABIAN HEAVY 28.2 .886 2.8 NIGERIA LIGHT 38.1 .834 0.2 API Degrees SP.Gravity % Sulfur Vol. % Gasoline Kerosene Lt. Gas Oil Hv. Gas Oils Bitumen Residuum 3 21 33 6 7 26 14 20 10 58 28 16 30 27 1

5 Useage of Asphalt Canadian market (1999).... 3.75 millions of t/year
USA market (1999) millions of t/year World market ~ millions of t/year 80 ~ 90 % of asphalts are used in pavements 10 ~ 20 % of asphalts are used in roofing, waterproofing and for other purposes World: 2.0 ~ 2.5 billions t/year of asphalt paving mixes

6 Potential Asphalt Production from Heavy Oils in Western Canada
Recoverable heavy oil in Western Canada: 3.5 ~ 7.0 billions of tons Potential production of asphalt: ~ 2800 millions of tons Price of asphalt in USA (spring 2001): US $ 100 ~ 150/t Price of asphalt in Canada (spring 2001): US $ 150 ~ 180/t Value of Western Canadian Asphalt: US $ 160 ~ 420 billion

7 Total Existing Length of Roads and Streets in USA
Total Mileage 6,243,000 kilometers (3,880,000 miles) Paved Mileage * 3,466,000 kilometers (2,154,000 miles) * 94% asphalt surfaced Total Existing Mileage of Roads and Streets in U.S.A. Portland Cement Concrete 200,000 kms (124,000 miles) Earth 603,000 kms (375,000 miles) Gravel or similar 2,174,000 kms (1,351,000 miles) Asphalt 3,267,000 kms (2,030,000 miles) Source: Federal High Administration

8

9 Crude Oil Throughput in US and Canadian Refineries

10 Paving Asphalt Production Capacity of US and Canadian Refineries

11 Composition and Structure of Asphalt
Physical and chemical character of asphalt is determined by: composition of crude oil method of crude oil and asphalt processing Asphalt: complex, multicomponent, colloidal system Asphalt is composed of a multitude species which differ by: molecular mass, chemical structure, polarity Molecular mass between D Carbon skeleton: atoms

12 Composition and Structure of Asphalt (Cont’d)
Composition varies considerably among asphalts manufactured from different crude oils The largest portion of paving asphalts are produced as vacuum residues with the cut point between 425°C and 565°C Relatively small difference in elemental analysis C: 80.0 ~ 85.0 % H: 7.8 ~ 8.3 % S: 1.0 ~ 7.0 % O: 2.7 ~ 5.0 %

13 Composition and Structure of Asphalt (Cont’d)
Group composition: saturates naphthene aromatics polar aromatics asphaltenes

14 Composition and Structure of Asphalt (Cont’d)
Hypothetical structure of asphaltene

15 Composition and Structure of Asphalt (Cont’d)
Unit sheet mass: D Cluster or particle mass: D Micelle mass: D

16 Properties of Asphalt Critical conditions during construction and service Construction: mixing spreading  appropriate viscosity compacting Service: plastic deformation (rutting) thermal cracking fatigue cracking water sensibility

17 Properties of Asphalt (Cont’d)

18 Specifications of Paving Asphalts
The role of specifications: specify properties that directly reflect asphalt behaviour express these properties in physical units provide limits for those properties to exclude poor performing products provide information from which the service performance can be predicted Important properties of asphalt: mechanical adhesive durability

19 Specifications of Paving Asphalts (Cont’d)
Conventional tests used for asphalt characterization: penetration, ductility, softening point R&B, flash point, spot test, Fraass breaking point….. Ageing characteristics: Thin Film Oven Test, Rolling Thin Film Oven Test, Pressure Aging Vessel… Rheological tests: Bending Beam Rheometer, Direct tension Test, Dynamic Shear Rheometer

20 Specifications of Paving Asphalts (Cont’d)
Beginning of specifications - around 1900 Classification of asphalts for commercial purposes in the first half of the century - exclusively conventional tests First: grading test - penetration at 25°C 1960’s in USA: grading test - viscosity at 60°C Canada: hybrid - penetration/viscosity 1990’s in USA : Superpave specification (“performance related”)

21 Classical Penetration- Based Specification
REQUIREMENTS FOR ASPHALT CEMENT FOR USE IN PAVEMENT CONSTRUCTION ASTM D946 Penetration Grade 40-50 60-70 85-100 Min Max Min Max Min Max Min Max Min Max 77°F(25°C) 100g, 5s Flash Point, °F (Cleveland open cup) Ductility at 77°F (25°C) 5cm/min, cm A --- Solubility in trichloroethylene, % Retained penetration after thin-film oven test, % Ductility at 77°F (25°C) 5cm/min, cm A --- after thin-film oven test A If ductility at 77°F (25°C) is less than 100 cm, material will be accepted if ductility at 60°F (15.5°C) is 100 cm minimum at the pull rate of 5 cm/min

22 Viscosity-Based Specification
REQUIREMENTS FOR ASPHALT CEMENT, VISCOSITY GRADED AT 140°F (60°C) ASTM D3381 Note: Grading based on original asphalt VISCOSITY GRADE AC-2.5 AC-5 AC-10 AC-20 AC-40 Viscosity, 140°F (60°C), P 250 ± ± ± ± ± 800 Viscosity, 275°F (135°C), min, cSt Penetration, 77°F (25°C), 100g, 5s, min Flash point, Cleveland open cup, min, °F (°C) 325 (163) 350 (177) 425 (219) 450 (232) 450 (232) Solubility in trichloroethylene, min, % Tests on residue from thin-film oven test: Viscosity, 140°F (60°C), max, P ,000 20, Ductility, 77°F (25°C), 5 cm/min, min, cm 100A A If ductility is less than 100, material will be accepted if ductility at 60°F (15.5°C) is 100 minimum at a pull rate of 5 cm/min

23 Canadian Federal Specification
Penetration at 25°C [dmm]

24 Canadian Federal Specification (Cont’d)

25 Canadian Federal Specification (Cont’d)
GRADES OF ASPHALT CEMENT Test Method ASTM D 5 D 2171 D 2170 Grades Requirements Penetration at 25°C 100g and 5s, 0.1mm *Viscosity at 60°C, Pa.s or *Viscosity at 135°C, mm2/s *Group A *Group B *Group C Flash Point (Cleveland Open Cup), °C Thin-film oven test, % loss in mass Penetration of residue at 25°C, 100g, 5s, 0.1mm, % of original penetration Solubility in trichloro- ethylene, % by mass 60-70 Min Max 80-100 Min Max Min Max Min Max Min Max Min Max User must specify either Figure 1 or Figure 2 for all asphalt grades. Both figures shall not be used simultaneously User must specify either Figure 1 or Figure 2 for all asphalt grades. Both figures shall not be used simultaneously D 92 D 1754 D 2042 * All requirements, except for viscosity at 60°C or at 135°C, are the same for Group A, B and C. Minimum viscosity is defined by the bottom line of each group as shown in Figure 1 or 2.

26 Superpave Specification
Strategic Highway Research Program: established by US Congress in 1987 as a five-year, $ 150 million research program to improve the performance and durability of roads in USA Outcome: asphalt binder performance related specification uses modern physical tests weather related traffic related

27 Superpave Specification (Cont’d)
Unlike older go - no go specifications Superpave specification determines different levels of asphalt quality The minimum quality needed for the particular road is also determined Presently already used in all states in USA (modification in California) Introduced in Ontario and Quebec Sooner or later will be used across Canada

28 Superpave Specification (Cont’d)
Further developments: Asphalt binder Expert Task Group (ETG) under the auspices of Transportation Research Board (US Academy of Sciences) and Federal Highway Administration development of parameters and testing methods better related to service performance ultimately: development of damage weighted performance models

29 Superpave Specification (Cont’d)
Superpave specification attempts to measure properties that are directly related to pavement field performance PERFORMANCE PROPERTY TEST EQUIPMENT Rotational Viscometer Handling Pump Flow Permanent Deformation Rutting Dynamic Shear Rheometer Fatigue Cracking Structural Cracking Bending Beam Rheometer Direct Tension Tester Thermal Cracking Low Temp Cracking

30 Dynamic Mechanical Analysis by Dynamic Shear Rheometer

31 Stiffness and m-value by Bending Beam Rheometer

32 Tensile Strength and T Critical by Direct Tension Tester

33 Superpave Asphalt Binder Grades
High Temperature Grades (Degrees C) PG46 PG52 PG58 PG64 PG70 PG76 PG82 Low Temperature Grades (Degrees C) -34, -40, -46 -10, -16, -22, -28, -34, -40, -46 -16, -22, -28, -34, -40 -10, -16, -22, -28, -34, -40 -10, -16, -22, -28, -34

34 Performance Graded Asphalt Binder Specification
Performance Grade PG PG PG58 Average 7-day Max Pavement Design Temperature, °C < < <58 Minimum Pavement Design Temperature, °C >-34 >-40 >-46 >-10 >-16 >-22 >-28 >-34 >-40 >-46 >-16 >-22 >-28 >-34 >-40 Flash Point Temp, T48: Min °C Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test rad/s, °C Mass Loss, Maximum, % G*/sin , Min, 2.20 kPa PAV Aging Temp, °C G*/sin , Min, 5000 kPa Test rad/s, °C Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test 60s, °C Direct Tension, TP3: Failure Strain, Min, 1.0% Test 1.0mm/min, °C Performance Grade PG PG PG58 Average 7-day Max Pavement Design Temperature, °C < < <58 Minimum Pavement Design Temperature, °C >-34 >-40 >-46 >-10 >-16 >-22 >-28 >-34 >-40 >-46 >-16 >-22 >-28 >-34 >-40 ORIGINAL BINDER Flash Point Temp, T48: Min °C Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test rad/s, °C ROLLING THIN FILM OVEN (T240) OR THIN FILM OVEN (T179) RESIDUE Mass Loss, Maximum, % G*/sin , Min, 2.20 kPa PRESSURE AGING VESSEL RESIDUE (PP1) PAV Aging Temp, °C G*/sin , Min, 5000 kPa Test rad/s, °C Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test 60s, °C Direct Tension, TP3: Failure Strain, Min, 1.0% Test 1.0mm/min, °C PG <61 >-10 >-16 >-22 >-28 >-34 >-40

35 Performance Graded Asphalt Binder Specification (Cont’d)
Performance Grade PG PG PG82 Average 7-day Max Pavement Design Temperature, °C < < <82 Minimum Pavement Design Temperature, °C >-10 >-16 >-22 >-28 >-34 >-40 >-10 >-16 >-22 >-28 >-34 >-10 >-16 >-22 >-28 >-34 ORIGINAL BINDER Flash Point Temp, T48: Min °C Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test rad/s, °C ROLLING THIN FILM OVEN (T240) OR THIN FILM OVEN (T179) RESIDUE Mass Loss, Maximum, % G*/sin , Min, 2.20 kPa PRESSURE AGING VESSEL RESIDUE (PP1) PAV Aging Temp, °C 100(110) (110) (110) G*/sin , Min, 5000 kPa Test rad/s, °C Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test 60s, °C Direct Tension, TP3: Failure Strain, Min, 1.0% Test 1.0mm/min, °C

36 Superpave PG Grades of Asphalts From Selected Crude Oils
Asphalt CGSB Pen T Official Grade 25°C High Low PG Grade Cold Lake 80/100A Bow Valley 80/100A Redwater 80/100B Foster Creek Cold Lake 120/150A Bow Valley 120/150A Redwater 120/150B Foster Creek Cold Lake 150/200A Bow Valley 150/200A Redwater 150/200B Foster Creek Service Temperature [°C]

37 Superpave PG Grades of Asphalts From Selected Crude Oils (Cont’d)
Service Temperature [°C] Asphalt CGSB Pen T Official Grade 25°C High Low PG Grade Cold Lake 200/300A Bow Valley 200/300B Redwater 200/300C Foster Creek Cold Lake 300/400A Bow Valley 200/300B Redwater 300/400C Foster Creek `

38 Conclusions Paving asphalt - important international commodity
Alberta - vast reserves of high quality paving asphalt New US asphalt specification recognizes the difference in product quality Strong demand for higher quality material Opportunity to export asphalt as a final material or as heavy crude oil with enhanced value of its distillation residue


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