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

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Presentation on theme: "PAVING ASPHALTS Origins, properties, manufacture and use Dr. Ludo Zanzotto Bituminous Materials Chair Faculty of Engineering University of Calgary May."— Presentation transcript:

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

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

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

4 Yield of Asphalt from Different Crude Oils API Degrees SP.Gravity % Sulfur BOSCAN VENEZUELA ARABIAN HEAVY NIGERIA LIGHT Gasoline Kerosene Lt. Gas Oil Hv. Gas Oils Bitumen Residuum Vol. %

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

6 Potential Asphalt Production from Heavy Oils in Western Canada l Recoverable heavy oil in Western Canada: 3.5 ~ 7.0 billions of tons l Potential production of asphalt: 1600 ~ 2800 millions of tons l Price of asphalt in USA (spring 2001): US $ 100 ~ 150/t l Price of asphalt in Canada (spring 2001): US $ 150 ~ 180/t l 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 l Physical and chemical character of asphalt is determined by: –composition of crude oil –method of crude oil and asphalt processing l Asphalt: complex, multicomponent, colloidal system l Asphalt is composed of a multitude species which differ by: –molecular mass, chemical structure, polarity l Molecular mass between D l Carbon skeleton: atoms

12 Composition and Structure of Asphalt (Contd) l Composition varies considerably among asphalts manufactured from different crude oils l The largest portion of paving asphalts are produced as vacuum residues with the cut point between 425°C and 565°C l 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 (Contd) l Group composition: –saturates –naphthene aromatics –polar aromatics –asphaltenes

14 Composition and Structure of Asphalt (Contd) Hypothetical structure of asphaltene

15 Composition and Structure of Asphalt (Contd) l Unit sheet mass: D l Cluster or particle mass: D l Micelle mass: D

16 Properties of Asphalt l 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 (Contd)

18 Specifications of Paving Asphalts l 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 l Important properties of asphalt: –mechanical –adhesive –durability

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

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

21 Classical Penetration- Based Specification MinMaxMinMaxMinMaxMinMaxMinMax 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 Penetration Grade REQUIREMENTS FOR ASPHALT CEMENT FOR USE IN PAVEMENT CONSTRUCTION ASTM D946 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 AC-2.5AC-5AC-10AC-20AC-40 Viscosity, 140°F (60°C), P250 ± 5050 ± ± ± ± 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 ,00020,000 Ductility, 77°F (25°C), 5 cm/min, min, cm100 A VISCOSITY GRADE REQUIREMENTS FOR ASPHALT CEMENT, VISCOSITY GRADED AT 140°F (60°C) ASTM D3381 Note: Grading based on original asphalt 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 (Contd)

25 Grades Requirements Penetration at 25°C 100g and 5s, 0.1mm *Viscosity at 60°C, Pa.s or *Viscosity at 135°C, mm 2 /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 Min Max Min Max Min Max Min Max Min Max Min Max Test Method ASTM D 5 D 2171 D 2170 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 GRADES OF ASPHALT CEMENT * 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 l 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 l Outcome: –asphalt binder performance related specification uses modern physical tests weather related traffic related

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

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

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, , -16, -22, -28, -34, -40, , -22, -28, -34, , -16, -22, -28, -34, , -16, -22, -28, -34

34 Performance Graded Asphalt Binder Specification Performance GradePG46PG52PG Average 7-day Max Pavement Design Temperature, °C<46<52<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 °C230 Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C135 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, %1.00 Dynamic Shear, TP5: G*/sin, Min, 2.20 kPa Test rad/s, °C PRESSURE AGING VESSEL RESIDUE (PP1) PAV Aging Temp, °C Dynamic Shear, TP5: G*/sin, Min, 5000 kPa Test rad/s, °C Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, Test 60s, °C Direct Tension, TP3: Failure Strain, Min, 1.0% Test 1.0mm/min, °C PG >-16>-22>-28>-34> Performance GradePG46PG52PG Average 7-day Max Pavement Design Temperature, °C<46<52<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 °C230 Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C135 Dynamic Shear, TP5: G*/sin, Min, 1.00 kPa Test rad/s, °C Mass Loss, Maximum, %1.00 Dynamic Shear, TP5: G*/sin, Min, 2.20 kPa Test rad/s, °C PAV Aging Temp, °C Dynamic Shear, TP5: G*/sin, Min, 5000 kPa Test rad/s, °C Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, Test 60s, °C Direct Tension, TP3: Failure Strain, Min, 1.0% Test 1.0mm/min, °C

35 Performance Graded Asphalt Binder Specification (Contd) Performance GradePG70PG76PG Average 7-day Max Pavement Design Temperature, °C<70<76<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 °C230 Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C135 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, %1.00 Dynamic Shear, TP5: G*/sin, Min, 2.20 kPa Test rad/s, °C PRESSURE AGING VESSEL RESIDUE (PP1) PAV Aging Temp, °C100(110)100(110)100(110) Dynamic Shear, TP5: G*/sin, Min, 5000 kPa Test rad/s, °C Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 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 AsphaltCGSBPen TOfficial Grade25°CHighLowPG Grade Cold Lake80/100A Bow Valley80/100A Redwater80/100B Foster Creek Cold Lake120/150A Bow Valley120/150A Redwater120/150B Foster Creek Cold Lake150/200A Bow Valley150/200A Redwater150/200B Foster Creek Service Temperature [°C]

37 Superpave PG Grades of Asphalts From Selected Crude Oils (Contd) AsphaltCGSBPen TOfficial Grade25°CHighLowPG Grade Cold Lake200/300A Bow Valley200/300B Redwater200/300C Foster Creek Cold Lake300/400A Bow Valley200/300B Redwater300/400C Foster Creek ` Service Temperature [°C]

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


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