ASPHALT 101 Robert B. McGennis, P.E. The HollyFrontier Companies Phoenix, AZ
The History of Asphalt
The HollyFrontier Companies Headquartered in Dallas, TX NYSE: HFC 5 complex/integrated refineries OK, NM, KS, WY, UT 457,000 bpd capacity 6 Asphalt Terminals Artesia, Albuquerque, Pena Blanca, NM Glendale, AZ Catoosa, OK Cheyenne, WY Who are those guys?
Once upon a time in Trinidad
Earliest Asphalt Binder Specs Addressed TLA (and similar) Color Solubility in carbon disulfide
Asphalt Manufacture Standard Oil Richmond, CA 1914
harder Penetration Test and Spec (1920s 1970s) Penetration 0 sec Penetration 5 sec 0.1 mm 100 g 100 g run test at 25 C (77 F) Grades: AASHO M20 40-50 60-70 85-100 120-150 200-300
The Problem with Pen Spec Consistency (pen) hard soft -15 pen 25 60 135 Temperature, C This is all we see in this system they all look the same! A B C
The Problem with Pen Spec Consistency (pen) hard pen soft -15 25 60 135 Temperature, C A B C
Asphalt Manufacture HollyFrontier El Dorado, KS 2015
Fractional Distillation 100 F Cooled Reflux Gas Carbons 4 Crude Oil 200 F Cooled Reflux 300 F Naphtha Gasoline 6 8 Cooled Reflux Kerosene 400 F 12 Cooled Reflux 500 F Liquid Vapor Diesel 16 Lubricating Oil Crude Furnace 600 F Heavy Gas Oil 36 44 Residue 700 F 70+ Distillation Column Source: Tom Shetina, HFC
What a Modern Refinery Does Volume Gain ~ 6% LPG ~ 2% LPG ~ 3% ~50% Gasoline ~ 25% Gasoline ~ 49% ~90% Jet & Diesel ~ 21% Lube Oil ~ 15% ~50% Jet & Diesel ~ 37% Residue ~ 37% Distilled WTI Crude The Refining Barrel 42 Gallons Residue ~ 8% Refined WTI Crude A refinery maximizes the conversion of crude oil into desirable products (transportation fuels)
Not all crude oils are created equal Lots of asphalt! No asphalt! Crude oil properties control asphalt quality!
More Asphalt Source: US Energy Information Administration
Atmospheric Bottoms Vaccum Distillation Gasoline Blending Atmospheric Distillation Sour H2O Stripper Other Gasses Light Naphtha Heavy Naphtha Gas Processing Hydrotreater Amine Treater Merox Treater Gas H2 Gas H2 Isomerization Unit Gas H2 Hydrotreater Refinery Fuel Gas Claus Sulfur Plant Isomerate Sweet Naphtha Propane Butane Gas Sulfur Catalytic Reformer High RVP Season H2 Complex/Integrated Refinery Reformate Sour Waters Steam H2S and NH# to Sulfur Plant Stripped Water Jet Fuel Kerosene Merox Treater Jet Fuel Gas H2 Crude Oil Diesel Gas H2 Diesel Hydrotreater Hydrocracked Gasoline Diesel (or NHT then Cat Reformer) Hydrocracker Distillate Isobutane Alkylation Unit Alkylate Gas Oil Light Cycle Oil Gas Olefins Gas H2 Light Gas Oil Gas H2 FCC Hydrotreater FCC Unit Gasoline FCC Gas Oil FCC Gasoline Hydrotreater Fuel Oil Treated Gasoline Vacuum Resid Heavy Gas Oil PDA Gas Oil Pitch Gas Oil Coker Gas Asphalt or Fuel Oil Naphtha (after hydrotreating) Petroleum Coke Source: Tom Shetina, HFC
Refinery Processes That Make Asphalt Separation Atmospheric distillation Vacuum distillation Solvent Deasphalting Unit (SDA, PDA) ROSE and other HCC Units Conversion Oxidizer Feed Pitch Coker, FCC, etc. NOT!!
Viscosity Test and Spec (1970s 1990s) Grades: AASHTO M226 AC 2.5, AC 5, AC 10, AC 20, AC 30, AC 40 Kinematic (275 F) Absolute (140 F) Do this at 140 F plus some other tests.
Viscosity Specifications Advantages viscosity is a more fundamental test characterizing asphalt over wider range of temperatures control of temperature susceptibility Disadvantages did not work well with modified asphalts (fact vs perception?) bad timing? something missing?
Bad Timing??? TRB Special Report 202 America s Highways: Accelerating the Search For Innovation (1984) Winnie, Texas, 1981 the procurement process for asphalt began more than 70 years ago this process does not accommodate improved adhesion, wetting, and oxidation characteristics the current knowledge of such desireable properties is not sufficient to be able to incorporate them in a procurement specification.
Something missing??? NCHRP Report 269, Paving with Asphalt Cements Produced in the 1980s, Epps, Button, and Gallaway, 1984 The physical properties of asphalt cements are more variable than 20 years ago, even though they remain within specification values; but variations in other factors may mask the influence of this variation on pavement performance.
Where Did PG Come From? (It s a relatively new thing! 1993 to present) Strategic Highway Research Program 1987-1993 $50 million research project by state DOTs primarily at universities Product was called Superpave Superior Performing Asphalt Pavements PG binder spec with new tests mix design system Adopted throughout all of US by now PG binder spec - AASHTO M320 mix design and analysis (no)
What s this PG All About? PG 64-22 High pavement temp (C) to protect against rutting Low pavement temp (C) to protect against thermal cracking
Another Way to Look at It Test asphalt binder at temps this layer feels (high, intermediate, low) Testing binder to get good performance for this layer at expected pavement temps.
PG Physical Property Tests Dynamic Shear Rheometer (high/med temp properties) Bending Beam Rheometer (low temp properties)
PG Plus Tests added to AASHTO M320 to ensure binder is polymer modified elastic recovery cold ductility toughness and tenacity force ductility compatibility others
Other Stuff in Asphalt Inorganic acids (e.g., PPA) Polymers and attendant stuff Construction Enhancers (e.g., WMA additives) Waste Post Consumer Products (e.g., scrap tires, shingles) Fillers and Fibers Antistripping agents Hydrocarbons Antioxidants Extenders (e.g., REOB) Rejuvenators
Log Log Stiffness, Viscosity, etc. Modification via polymer polymer modified Unmodified Log Temperature
Types of Polymers Elastic Type - SB diblock - SBS - SBR latex - Waste rubber Plastic Type - EVA - polyethylene
Polymer Modified Asphalt (Elastic) Advantages Significant Disadvangates performance history Can be challenging to Elastic effect manufacture Improved cohesion Compatibility can be a problem t = s tan (f) + c Tougher to handle Many specs designed Sometimes not heat stable around stretchy Challenge to emulsify polymers (no Sometimes supply/price mysteries) not stable Favorable co-modifier Relatively expensive with others (e.g., PPA)
Millions of Tons Sold Asphalt Usage in U.S. (1963-2015) 40 35 30 25 2017 (tons) 21.7 MM Total 18.7 MM Paving 20 15 10 5 Source: Asphalt Institute 0 1960 1970 1980 1990 2000 2010 2020
The Future? Asphalt Manufacture heavier, sour crude more blending to grade AASHTO M332 (new PG) compliance vs stiffness of binder eliminate ER test? no more bumping of grades More PG+ Delta T cee (DTc) better lab aging (hopefully) compatibility tests
The Future? Modified Binders ability to quantify effect on mix HIMA More incorporation of waste post consumer stuff Life Cycle Assessment
Thank you come see me in Arizona some time!