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PAVING ASPHALTS Origins, properties, manufacture and use. Dr. Ludo Zanzotto Bituminous Materials Chair Faculty of Engineering University of Calgary May 2001. Historical Background. One of the oldest engineering materials “asphaltos” - sticky, firm - Greek
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PAVING ASPHALTSOrigins, properties, manufacture and use Dr. Ludo Zanzotto Bituminous Materials Chair Faculty of Engineering University of Calgary May 2001
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 (2500 - 1500 B.C.) • Noah’s ark - waterproofing • Tower of Babel - mortar • Paving
Sources and Manufacture of Asphalt • Sources • 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
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
Useage of Asphalt • Canadian market (1999).... 3.75 millions of t/year • USA market (1999)............38.00 millions of t/year • World market................~ 130.00 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
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: 1600 ~ 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
Total Existing Length of Roads and Streets in USA Total Mileage6,243,000 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
Paving Asphalt Production Capacity of US and Canadian Refineries
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 400 - 3000 D • Carbon skeleton: 25 - 150 atoms
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 %
Composition and Structure of Asphalt (Cont’d) • Group composition: • saturates • naphthene aromatics • polar aromatics • asphaltenes
Composition and Structure of Asphalt (Cont’d) Hypothetical structure of asphaltene
Composition and Structure of Asphalt (Cont’d) • Unit sheet mass: 1 000 - 4 000 D • Cluster or particle mass: 4 000 - 10 000 D • Micelle mass: 40 000 - 40 000 000 D
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
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
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
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”)
Classical Penetration- Based Specification REQUIREMENTS FOR ASPHALT CEMENT FOR USE IN PAVEMENT CONSTRUCTION ASTM D946 Penetration Grade 40-50 60-70 85-100 120-150 200-300 Min Max Min Max Min Max Min Max Min Max Penetration @ 77°F(25°C) 100g, 5s 40 50 60 70 85 100 120 150 200 300 Flash Point, °F (Cleveland open cup) 450 --- 450 --- 450 --- 425 --- 350 --- Ductility at 77°F (25°C) 5cm/min, cm 100 --- 100 --- 100 --- 100 --- 100A --- Solubility in trichloroethylene, % 99 --- 99 --- 99 --- 99 --- 99 --- Retained penetration after thin-film 55+ --- 52+ --- 47+ --- 42+ --- 37+ ---oven test, % Ductility at 77°F (25°C) 5cm/min, cm --- --- 50 --- 75 --- 100 --- 100A ---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
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 ± 50 50 ± 100 1000 ± 200 2000 ± 400 4000 ± 800 Viscosity, 275°F (135°C), min, cSt 80 110 150 210 300 Penetration, 77°F (25°C), 100g, 5s, min 200 120 70 40 20 Flash point, Cleveland open cup, min, °F (°C) 325 (163) 350 (177) 425 (219) 450 (232) 450 (232) Solubility in trichloroethylene, min, % 99 99 99 99 99 Tests on residue from thin-film oven test: Viscosity, 140°F (60°C), max, P 1250 2500 5000 10,000 20,000 Ductility, 77°F (25°C), 5 cm/min, min, cm 100A 100 50 20 10 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
Canadian Federal Specification Penetration at 25°C [dmm]
Canadian Federal Specification (Cont’d) GRADES OF ASPHALT CEMENT Test MethodASTM D 5 D 2171 D 2170 Grades Requirements Penetration at 25°C100g 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 60 70 80-100 Min Max 80 100 120-150 Min Max 120 150 150-200 Min Max 150 200 200-300 Min Max 200 300 300-400 Min Max 300 400 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 230 --- --- 0.8 52 --- 99 --- 230 --- --- 0.85 47 --- 99 --- 220 --- --- 1.3 42 --- 99 --- 220 --- --- 1.3 40 --- 99 --- 175 --- --- 1.5 37 --- 99 --- 175 --- --- 1.5 35 --- 99 --- 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.
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
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
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
Superpave Specification (Cont’d) • Superpave specification attempts to measure properties that are directly related to pavement field performance PERFORMANCE PROPERTY TEST EQUIPMENT Handling Pump Rotational Viscometer Flow Rutting Permanent Deformation Dynamic Shear Rheometer Fatigue Cracking Structural Cracking Thermal Cracking Bending Beam Rheometer Direct Tension Tester Low Temp Cracking
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, -40 -10, -16, -22, -28, -34 -10, -16, -22, -28, -34
Performance Graded Asphalt Binder Specification Performance Grade PG46 PG52 PG58 -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 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 °C 230 Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C 135 Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test temp@10 rad/s, °C 46 52 58 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 temp@10 rad/s, °C 46 52 58 PRESSURE AGING VESSEL RESIDUE (PP1) PAV Aging Temp, °C 90 90 100 Dynamic Shear, TP5: G*/sin , Min, 5000 kPa Test temp@10 rad/s, °C 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test Temp, @ 60s, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 Direct Tension, TP3: Failure Strain, Min, 1.0% Test Temp@ 1.0mm/min, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 Performance Grade PG46 PG52 PG58 -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 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 °C 230 Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C 135 Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test temp@10 rad/s, °C 46 52 58 Mass Loss, Maximum, % 1.00 Dynamic Shear, TP5: G*/sin , Min, 2.20 kPa Test temp@10 rad/s, °C 46 52 58 PAV Aging Temp, °C 90 90 100 Dynamic Shear, TP5: G*/sin , Min, 5000 kPa Test temp@10 rad/s, °C 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test Temp, @ 60s, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 Direct Tension, TP3: Failure Strain, Min, 1.0% Test Temp@ 1.0mm/min, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 PG64-10 -16 -22 -28 -34 -40 <61>-10 >-16 >-22 >-28 >-34 >-40 64 64 100 31 28 25 22 19 16 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30
Performance Graded Asphalt Binder Specification (Cont’d) Performance Grade PG70 PG76 PG82 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 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 °C 230 Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C 135 Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test temp@10 rad/s, °C 70 76 82 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 temp@10 rad/s, °C 70 76 82 PRESSURE AGING VESSEL RESIDUE (PP1) PAV Aging Temp, °C 100(110) 100(110) 100(110) Dynamic Shear, TP5: G*/sin , Min, 5000 kPa Test temp@10 rad/s, °C 34 31 28 25 22 19 37 34 31 28 22 40 37 34 31 28 Physical Hardening REPORT Creep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test Temp, @ 60s, °C 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Direct Tension, TP3: Failure Strain, Min, 1.0% Test Temp@ 1.0mm/min, °C 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24
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 80 64.6 -27.5 92.1 64-22 100 62.4 -29.1 91.5 58-28 Bow Valley 80/100A 80 63.1 -24.8 87.9 58-22 100 60.9 -26.7 87.6 58-22 Redwater 80/100B 80 59.7 -25.5 85.2 58-22 100 57.8 -26.2 84.0 52-22 Foster Creek 80 63.7 -26.6 90.3 58-22 100 61.5 -28.2 89.7 58-28 Cold Lake 120/150A 120 60.5 -30.5 91.0 58-28 150 58.1 -32.2 90.3 58-28 Bow Valley 120/150A 120 59.0 -28.3 87.3 58-28 150 57.7 -30.2 87.9 52-28 Redwater 120/150B 120 56.1 -27.0 83.1 52-22 150 54.0 -28.2 82.2 52-28 Foster Creek 120 59.7 -29.5 89.2 58-28 150 57.3 -31.2 88.5 52-28 Cold Lake 150/200A 150 58.1 -32.2 90.3 58-28 200 54.8 -34.1 88.9 52-34 Bow Valley 150/200A 150 57.7 -30.2 87.9 52-28 200 53.5 -32.5 86.0 52-28 Redwater 150/200B 150 54.0 -28.2 82.2 52-28 200 51.2 -29.7 80.9 -- Foster Creek 150 57.3 -31.2 88.5 52-28 200 54.2 -33.4 87.6 52-28 Service Temperature [°C]
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 200 54.8 -34.1 88.9 52-34 300 49.8 -36.1 85.9 46-34 Bow Valley 200/300B 200 53.5 -32.5 86.0 52-28 300 48.6 -35.0 83.6 46-34 Redwater 200/300C 200 51.2 -29.7 80.9 -- 300 47.0 -31.7 78.7 -- Foster Creek 200 54.2 -33.4 87.6 52-28 300 49.4 -36.5 85.9 52-34 Cold Lake 300/400A 300 49.8 -36.1 85.9 46-34 400 46.0 -37.2 83.2 46-34 Bow Valley 200/300B 300 48.6 -35.0 83.6 46-34 400 44.9 -36.4 81.3 -- Redwater 300/400C 300 47.0 -31.7 78.7 -- 400 43.7 -32.9 76.6 -- Foster Creek 300 49.4 -36.5 85.9 52-34 400 45.8 -38.8 84.6 46-34 `
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