Selection and Use of Thin Surface Treatments Stephen R. Mueller, P.E. Pavement and Materials Engineer FHWA Resource Center (Lakewood, Colorado) Steve.Mueller@fhwa.dot.gov Federal Highway Administration
Navigating the Waves of Change Asset Management Philosophy Network-wide Use Economic Principles Preservation First Integrate Programs Concentrate on Corridors Define Design Life in terms of Traffic
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Goals and Objectives of this Presentation: Present information on the various surface treatments available for preventive maintenance focusing on project selection.
Presentation Outline 1. Introduction and Federal Interest 2. Pavement Preservation Concepts and how they relate to Project Selection 3. Common Thin Surface Treatments 4. Methodologies for Selection 5. Concluding Remarks
Pavement Condition Performance Curves / Costs of Repairs 40% Drop in Quality $1.00 to Preserve / Maintain Here 75% of Life 40% Drop in Quality 12% $4-$5? $11-$14? $32-$58? Here! Terminal Serviceability T 0 T 1 Initial Design Pavement Life
The Pavement Preservation Concept Original Pavement Very Good Good Fair Poor Rehabilitation Trigger Very Poor Time (Years)
A QUICK CHECK OF THE HEALTH OF YOUR HIGHWAY NETWORK
Pavement Preservation Guidelines Type of Activity Increase Capacity Increase Strength Reduce Aging Restore Serviceability New Construction Reconstruction Major (Heavy) Rehabilitation X X X X X X X X X X X Structural Overlay X X X Pavement Preservation Minor (Light) Rehabilitation X X Preventive Maintenance X X Routine Maintenance Corrective (Reactive) Maintenance Catastrophic Maintenance X X X
Preservation Activities - Examples Asphalt: Chip Seals Fog Seals Slurry Seals Surface Seals Micro-Surfacing Thin Overlays Profile Milling Crack Sealing PCC: Joint Resealing Crack Sealing Spall Repair Dowel Bar Retrofit Full and Partial Depth Repair Diamond Grinding
Surface Treatments Purpose Typically used to: Seal cracks Waterproof surface Improve friction Improve rideability Rejuvenate surface
Surface Treatments Types Fog seal Slurry seal Chip seal Microsurfacing CIR/HIR Mill and Thin HMA Overlay Others?
Key Factors to Consider 1. Sealing Needed? 2. Cracking Types / Extent? 3. Rutting? 4. Friction/Texture Issues? 5. Other Surface Defects? ---------------- Treatment Life? Life Extension of Underlying Pavement? Cost Effectiveness?
Sand Patch (or Sand Circle ) Test A procedure for determining pavement surface macrotexture through the spreading of a predetermined volume of sand or glass bead material on the pavement surface of a given area. (ASTM E965)
Fog Seal Description Light application of diluted, slow-setting asphalt emulsion without aggregate cover Purpose Seal pavement Inhibit raveling Enrich hardened/oxidized asphalt Provide delineation with shoulder
Slurry Seal Description Mixture of well-graded aggregate and an asphalt emulsion Purpose Seal surface cracks Correct raveling/oxidation Fill minor surface irregularities and restore friction
Chip Seal Description Application of asphalt and aggregate chips rolled onto the pavement Purpose Seal pavement Enrich hardened/oxidized asphalt Retard reflection cracking on HMA overlays Improve surface friction
Microsurfacing Description Mixture of high-quality aggregates and polymer-modified emulsion binder Purpose Seal pavement surface Fill ruts/minor surface irregularities Inhibit raveling and surface oxidation Improve surface friction
Recycling Treatments Purpose Typically used to Rework HMA to a depth of 1 to 4 inches. Correct surface distresses Improve profile, crown, and slope
Recycling Treatments Types (for Preservation) Cold In-Place Recycling Hot In-Place Recycling
Cold In-Place Recycling Description Milling, rejuvenating, and replacement of the top portion of the HMA surface (performed without heat) Purpose Rework HMA to depth of 2 4 inches. Correct surface distresses. Improve profile, crown, and cross-slope.
Hot In-Place Recycling Description Milling, rejuvenating, and replacement of the top portion of the HMA surface (performed with heat) Purpose Rework HMA to depth of 1 to 2 inches. Correct surface distresses. Improve profile, crown, and cross-slope.
Milling with Thin HMA Overlay Description Application of a new HMA wearing course after milling of the top portion of the HMA surface Purpose Improve rideability and surface friction. Improve profile, crown, and cross-slope. OGFC reduce hydroplaning and tire splash.
What is Best? Right pavement, Right treatment, Right time. Where are these determined?
Right Pavement (Project Selection) Current condition Age Expected life Construction quality Traffic Environment Others
Right Treatment (Treatment Selection) Decision tools Trees Matrices Other factors Materials Contractors Delay Costs Benefits Experience
Right Time (Optimization) Time-based schedules Decision tools (condition-based) Recommended Reading: Optimal Timing of Pavement Preventive Maintenance Treatment Applications NCHRP Report 523 (February 2005)
Pavement Condition Preventive vs. Reactive Maintenance Preventive Maintenance Reactive Maintenance Time
Time-Based Schedule Example New York State-Initial Guidelines Treatment Type Appl. Cycle, yrs HMA pavement crack sealing Thin HMA overlays (38 mm [1.5 in]) Surface treatments of HMA pavements Surface treatments of shoulders Clean drainage 4 12 4 4 10
HMA Decision Tree Example Raveling and Weathering Structural Condition Adequate Not Adequate ADT <1000 1000 to 5000 >5000 Fog Seal or Chip Seal Fog Seal or Chip Seal or Microsurfacing Fog Seal or Microsurfacing Not Appropriate for Preventive Maintenance
Training 4 NHI Classes on Pavement Preservation The Preventive Maintenance (PM) Concept NHI Course #131054 Selecting Pavements for Preventive Maintenance NHI Course #131058 Design and Construction of Quality PM Treatments NHI Course #131103 Integrating PM into Pavement Management Systems NHI Course #131104 www.nhi.fhwa.dot.gov
FHWA WEBSITE www.fhwa.dot.gov/preservation www.fhwa.dot.gov/pavement
Pavement Preservation Mantra: Apply the right treatment... to the right road at the right time. Think Engineering and Economics!
Preservation and Asset Management won t bring short-term glory, but they will bring long-term satisfaction!
Questions?
THANK YOU For more information contact: Steve Mueller FHWA Resource Center Telephone: (720) 963-3213 e-mail: steve.mueller@fhwa.dot.gov www.fhwa.dot.gov/preservation www.fhwa.dot.gov/resourcecenter