Background Asphalt Soluble in petroleum products Generally a byproduct of petroleum distillation process Can be naturally occurring Tar Resistant to petroleum products Generally by-product of coke (from coal) production
Petroleum-Based Asphalts Asphalt is waste product from refinery processing of crude oil Sometimes called the bottom of the barrel Properties depend on: Refinery operations Composition crude source-dependent Gasoline Naphtha Kerosene Diesel Motor Oils Lube Oil Barrel of Crude Oil Asphalt Asphalt Cement Components Asphaltenes Large, discrete solid inclusions (black) High viscosity component Resins Semi-solid or solid at room temperature» Fluid when heated» Brittle when cold Oils Colorless liquid Soluble in most solvents Allows asphalt to flow
Refinery Operation LIGHT DISTILLATE FIELD STORAGE TOWER DISTILLATION REFINERY PUMPING STATION MEDIUM DISTILLATE HEAVY DISTILLATE GAS STORAGE PETROLEUM SAND AND WATER TUBE HEATER CONDENSERS AND COOLERS AIR STILL RESIDUUM OR AIR BLOWN ASPHALT PROCESS UNIT ASPHALT CEMENTS FOR PROCESSING INTO EMULSIFIED AND CUTBACK ASPHALTS Types Asphalt cements Generally refinery produced material Air blown asphalt cements Cutbacks Asphalt cements cut with petroleum solvents Emulsions Mixture of asphalt cement, water, and emulsifying agent
Air Blown Asphalt Cement Cutbacks Rapid cure (RC) (Naphtha or Gasoline) High volatility of solvent Tack coats, surface treatments Medium cure (MC) (Kerosene) Moderate volatility Stockpile patching mix Slow cure (SC) (Low viscosity oil) Low volatility Prime coat, dust control
Emulsions Emulsifier gives surface charge to asphalt droplets suspended in water medium Anionic» Negative charge» Alkaline» Good with limestones (positive charge) Cationic» Positive charge» Acid» Good with silica gravels (negative charge) Containerized
Emulsion Formation Asphalt Dispersed in Water Sheared to a fine particle size
Particle Sizing 1-5 micron Poor Good
Cold recycling Hot Bitumen Water Air Foamed Bitumen 2-3% cold water injected into the hot bitumen will produce foam with an expansion of 10 to 20 times of the original volume
Purchasing of Asphalt Cements Need to be able to specify desirable characteristics Desirable characteristics have evolved over time and with increasing technological advances Purchasing requires specifications Early Specifications Lake Asphalts Appearance Solubility in carbon disulfide Petroleum asphalts (early 1900 s) Consistency»Chewing»Penetration machine - Measure consistency
Penetration Testing Sewing machine needle Specified load, time, temperature 100 g Penetration in 0.1 mm Initial After 5 seconds Penetration Specification Five Grades 40-50 60-70 85-100 120-150 200-300
Viscosity Graded Specifications Definition Viscosity: the ratio between the applied shear stress and the rate of shear. η = τ / γ
Types of Viscosity Tubes Asphalt Institute Tube Zietfuchs Cross-Arm Tube Testing Absolute viscosity U-shaped tube with timing marks & filled with asphalt Placed in 60C bath Vacuum used to pull asphalt through tube Time to pass marks Viscosity in Pa s (Poise)
Penetration Grades Viscosity, 60C (140F) 100 50 10 40 50 60 70 85 100 120 150 200 300 AC 40 AC 20 AC 10 AC 5 AC 2.5 AR 16000 AR 8000 AR 4000 AR 2000 AR 1000 5 Short Term Binder Aging Rolling Thin Film Oven Simulates aging from hot mixing and construction Control Fan Air jet Bottle carriage 1.3. 9
Penetration 0 sec 5 sec Penetration 100g 100g Viscosity vacuum AC OR AR 1.1. 17 Consistency (pen or viscosity) hard Pen limit Viscosity limit Lower viscosity limit soft A B C -15 25 60 135 Temperature, C 3-60/70 AC Asphalts meeting specs 1.1. 18
SUPERPAVE -20 20 60 135 Pavement Temperature, C Cracking Fatigue Rutting Viscosity Workability PAV PAV Fresh & RTFO Fresh 1.3. 3 Torque Motor Rotational Viscometer (Brookfield) Inner Cylinder Thermosel Environmental Chamber Digital Temperature Controller
Viscosity, Pa s 10 5 Mixing/Compaction Temps 1.5.3.2 Compaction Range Mixing Range.1 100 110 120 130 140 150 160 170 180 190 200 Temperature, C SUPERPAVE -20 20 60 135 Pavement Temperature, C Cracking Fatigue Rutting Viscosity Workability PAV PAV Fresh & RTFO Fresh 1.3. 3
Short Term Binder Aging Rolling Thin Film Oven Simulates aging from hot mixing and construction Control Fan Air jet Bottle carriage 1.3. 9 Pressure Aging Vessel Rack of individual pans (50g of asphalt / pan) Bottom of pressure aging vessel Vessel Lid Components 1.3. 19
Motor Parallel Plates Area for Liquid Bath
SUPERPAVE -20 20 60 135 Pavement Temperature, C Cracking Fatigue Rutting Viscosity Workability PAV PAV Fresh & RTFO Fresh 1.3. 3 Deflection Transducer Control and Data Acquisition Asphalt Beam Air Bearing Load Cell Fluid Bath Loading Frame Supports Temperature Detector
Bending Beam Rheometer Equipment Fluid Bath Loading Ram Cooling System Direct Tension Test Courtesy of FHWA
SUPERPAVE -20 20 60 135 Pavement Temperature, C Cracking Fatigue Rutting Viscosity Workability PAV PAV Fresh & RTFO Fresh 1.3. 3
Superpave Asphalt Binder Specification The grading system is based on Climate PG 70-10 Performance Grade Min pavement temperature Average 7-day max pavement temperature Binder Selection & Tests Select Grade climate reliability PG-70-10 PG-76-10 verify Grade G*, δ, S, m, etc. temp/vis. profile PG-64-22
TURAIF AL-QURAYYAT ARAR AL-JAWF R. AL-QURAYYAT R. AL-JAWF RAFHA NORTH BORDER R. TABOUK KUWAIT TABOUK R. AL-QAISUMAH HAIL R E D S E A AL-WAJH MADINAH R. YANBU MADINAH PG 70-10 MAKKAH R. JEDDAH MAKKAH TAIF HAIL R. AL-BAHA R. BAHA BURAYDAH AL-QASSIM R. AL-DAWADMI BISHA ASIR R. RIYADH RIYADH REGION PG 64-10 PG 70-10 SULAYYIL KHAMIS MUSHAYT NAJRAN R. ABHA NAJRAN SHARURAH JIZAN R. JIZAN DHAHRAN HAFUF ARABIAN GULF QATAR PG 76-10 EASTERN PROVINCE U A E O M A N GULF OF OMAN Tentative Temperature Zoning for Asphalt Binder Specifications for the Gulf Countries. Questions -?