Dr. Wa'el M. Albawwab ECGD4228 Transportation Engineering II Summer 2008 Sat. 15:30-18:30 PM K004
Dr. Wa'el M. Albawwab Pavement Purposes and Significance Pavement Conditions Pavement Types Paving Materials Lecture 4
Dr. Wa'el M. Albawwab Pavement Materials Pavement Structural Analysis Pavement Design Pavement Maintenance Pavement Rehabilitation Pavement Management Systems Pavement Engineering
Dr. Wa'el M. Albawwab Road pavements are structures designed and built on existing grounds to facilitate smooth, safe, reliable, and convenient traffic flows. General Definition
Dr. Wa'el M. Albawwab Flexible Pavements Rigid Pavements Mixed Pavements Categories of Road Paving
Dr. Wa'el M. Albawwab Category I: Flexible Pavements
Dr. Wa'el M. Albawwab Hot mix asphalt (HMA) pavements Considered as flexible structures since the total pavement structure flexes to conform the applied traffic loads Categories of Road Paving Flexible Pavements
Dr. Wa'el M. Albawwab Traffic Lanes Auxiliary Lanes Parking Lots Shoulders Ramps Typical Applications of Flexible Pavements
Dr. Wa'el M. Albawwab Adjusts to limited differential settlements Easy repair and maintenance Maintains non-slip properties More convenient for drivers Tolerates a wide range of temperatures Advantages of Flexible Pavements
Dr. Wa'el M. Albawwab Flexibility and cohesion decrease with time Requires resurfacing sooner than rigid paving Normally not suitable for dominantly wet areas Disadvantages of Flexible Pavements
Dr. Wa'el M. Albawwab Types of Flexible Pavements Dense Graded
Dr. Wa'el M. Albawwab Types of Flexible Pavements Open Graded
Dr. Wa'el M. Albawwab Types of Flexible Pavements Gap Graded
Dr. Wa'el M. Albawwab Surfaces of Flexible Pavements
Dr. Wa'el M. Albawwab Surfaces of Flexible Pavements
Dr. Wa'el M. Albawwab Surfaces of Flexible Pavements
Dr. Wa'el M. Albawwab Structure of Flexible Pavements
Dr. Wa'el M. Albawwab Load Distribution in Flexible Pavements
Dr. Wa'el M. Albawwab Load Effect in Flexible Pavements
Dr. Wa'el M. Albawwab Configuration of Flexible Pavements Heavy Traffic Volumes
Dr. Wa'el M. Albawwab Configuration of Flexible Pavements Light Traffic Volumes
Dr. Wa'el M. Albawwab Asphalt (Bitumen) is a waste product from refinery processing of crude oil Sometimes called the “bottom of the barrel” Properties depend on: Composition of crude source Refinery operations Composition of Flexible Pavements Bituminous Materials
Dr. Wa'el M. Albawwab Configuration of Flexible Pavements Refined Crude Oil
Dr. Wa'el M. Albawwab Bituminous Binders Asphalt Cement Cutback Asphalt Emulsified Asphalt Asphalt Concrete (Binder + Aggregate) Composition of Flexible Pavements Bituminous Materials
Dr. Wa'el M. Albawwab Asphalt cements: Generally refinery produced material - Air blown Cutbacks: Asphalt cements “cut” with petroleum solvents Emulsions: Mixture of asphalt cement, water, and emulsifying agents Composition of Flexible Pavements Bituminous Binders
Dr. Wa'el M. Albawwab Composition of Flexible Pavements Chemical Composition of Asphalt Cement ElementPortion Carbon 85 % Hydrogen 10 % Sulfur % Nitrogen % Oxygen % Vanadium < 1400 ppm Nickel < 110 ppm
Dr. Wa'el M. Albawwab 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 Composition of Flexible Pavements Components of Asphalt Cement
Dr. Wa'el M. Albawwab 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 Composition of Flexible Pavements Cutbacks
Dr. Wa'el M. Albawwab Composition of Flexible Pavements Emulsified Asphalts
Dr. Wa'el M. Albawwab Hot mix asphalt concrete (HMAC): Asphalt cement and aggregate heated to 300°F & mixed Cold mix: Aggregate mixed with liquid asphalt Surface treatments (or seal coats) Prime coats and tack coats Slurry seals Crack seals Composition of Flexible Pavements Different Usages
Dr. Wa'el M. Albawwab Consistency, measured by Kinematic viscosity at 135°C (in mm 2 /sec) Absolute viscosity at 60°C (in 0.1 Pa.Sec) Penetration Test at 25°C (in 0.1 mm) Aging during production of HMAC & service Rolling Thin-Film-Oven-Test (RTFOT) Durability, which is the resistance to Oxidation, volatilization, age-hardening Stripping of asphalt from aggregate Lottman Test Composition of Flexible Pavements Testing of Asphalt Properties
Dr. Wa'el M. Albawwab Flexible Pavements Testing of Subgrade Properties Characterized by strength and/or stiffness California Bearing Ratio (CBR) Measures shearing resistance Typical values: % Resilient Modulus (M R ) Measures stress-strain relationship Typical values: 3, ,000 psi (20 – 275 MPa)
Dr. Wa'el M. Albawwab GradeCBR M R (psi) Typical Description Good ≥ 10 20,000 Gravels, crushed stone and sandy soils. GW, GP, GM, SW, SP, SM soils are often in this category. Fair 5 – 9 10,000 Clayey gravel and clayey sand, fine silt soils. GM, GC, SM, SC soils are often in this category. Poor 3 – 5 5,000 Fine silty sands, clays, silts, organic soils. CL, CH, ML, MH, CM, OL, OH soils are often in this category. Testing of Subgrade Properties
Dr. Wa'el M. Albawwab Construction of Flexible Pavements
Dr. Wa'el M. Albawwab Construction of Flexible Pavements
Dr. Wa'el M. Albawwab Construction of Flexible Pavements
Dr. Wa'el M. Albawwab Construction of Flexible Pavements
Dr. Wa'el M. Albawwab Construction of Flexible Pavements
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Condition vs. Time
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Low Severity Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Moderate Severity Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements High Severity Spalled Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Chicken Wire / Alligator Pattern Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Longitudinal Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Transverse Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Blocked Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Edge Fatigue Cracking
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Rutting
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Rutting
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Shoving (Heavy Weight Impact)
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Shoving (Heavy Weight Impact)
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Potholes
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Water Bleeding and Flushing (Pumping)
Dr. Wa'el M. Albawwab Distresses in Flexible Pavements Frost Thawing
Dr. Wa'el M. Albawwab Rehabilitation of Flexible Pavements Resurfacing