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Completed projects

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Title: Evaluation of Interlayer Bonding in HMA Pavements
Project ID:0092-02-13
Publication Date: June 2008
Investigator: Yusuf Mehta, Rowan University
WisDOT Contact: Thomas Brokaw
Final Report (1 MB)
Research Brief (232 KB)
Researchers sought to identify and locate interlayer bonding failures in the field and recommend treatment and prevention strategies. Results demonstrated that WisDOT could use data from a falling weight deflectometer to identify and locate potential and existing interlayer bonding failures.

Title: Testing Wisconsin Asphalt Mixtures for the AASHTO 2002 Mechanistic Design Procedure
Project ID: 0092-04-07
Publication Date: March 2008
Investigator: R. Christopher Williams, Iowa State University
WisDOT Contact: Tom Brokaw
Final Report (1.8 MB)
Research Brief (214 KB)
Investigators obtained dynamic modulus values for existing Wisconsin HMA pavements to be used as design inputs in the new AASHTO Mechanistic-Empirical Design Guide. Research confirmed that a number of existing design practices will continue to work well as WisDOT moves toward M-E adoption. 

Title: Perpetual Pavement Instrumentation for the Marquette Interchange Project-Phase 1
Project ID: 0092-06-01
Publication Date: February 2008
Investigator: James Crovetti, Marquette University
WisDOT Contact: Len Makowski
Final Report (2.6 MB)
Research Brief (270 KB)
Video (5 Minutes 49 Seconds)
The purpose of this study was to monitor an in-service hot-mix asphalt perpetual pavement to ensure it is performing according to design specifications. Researchers designed and installed a complete sensor array in a section of HMA perpetual pavement with all but two sensors remaining fully operational, providing an accumulation of valuable performance data.

Title: Development of In-Place Permeability Criteria for HMA Pavement in Wisconsin
Project ID: 0092-06-02
Publication Date: November 2007
Investigator: Bob Schmitt, University of Wisconsin-Platteville
WisDOT Contact: Judie Ryan
Final Report (727 KB)
Research Brief (235 KB)
Researchers sought to determine the full extent of the HMA permeability problem in Wisconsin using both "as-built" and "in-place" data. Test results showed uniformly low permeability rates for both water and air. Investigators could not define acceptance criteria based on measured permeability values due to nearly identical in-place permeability values across test sections. The research expanded WisDOT's knowledge of permeability and performance on in-service HMA and provided direction for further research.

Title: Test Method to Determine Aggregate/Asphalt Adhesion Properties and Potential Moisture Damage
Project ID: 0092-05-12
Publication Date: November 2007
Investigator: Andrew Hanz, University of Wisconsin-Madison
WisDOT Contact: Judie Ryan
Final Report (2.1 MB)
Research Brief (187 KB)
This project evaluated whether a nonmechanical screening test could replace the traditional Tensile Strength Ratio test in determining HMA mixes that display resistance to moisture damage. Researchers learned that neither the stripping or fracture energy tests were viable alternatives to the TSR test. Researchers estimate that engineers would spend 30 to 50 percent less time on mixture evaluations by using a simple screening test for moisture susceptibility; however, no alternative to the TSR test can be recommended at this time.

Title: Field Evaluation of Wisconsin Modified Binder Selection Guidelines
Project ID: 0092-03-13
Publication Date: October 2007
Investigator: Hussain Bahia, University of Wisconsin-Madison
WisDOT Contact: Thomas Brokaw
Final Report (343 KB)
Research Brief (224 KB)
Two important approaches WisDOT pavement engineers use to select the appropriate hot-mix asphalt have been the use of AASHTO performance graded binders (the materials that bind the aggregates to each other in an asphalt pavement) and the use of high-tech modifiers in those binders. Researchers performed field tests to validate binder grade selection guidelines for Wisconsin pavements and confirm the impact of various modifiers on asphalt performance. The field results included valuable data in the areas of mixing and compaction, fatigue, low-temperature cracking and rutting.  Researchers also delivered an electronic database of pavement materials and performance that WisDOT can update as the project sites age, adjusting design practices as necessary to reflect the new data.

Title: Life Cycle Cost Analysis of SMA Pavements and SMA Application Guidelines
Project ID: 0092-04-06
Publication Date: February 2007
Investigator: Harold Von Quintus, ERES Consultants
WisDOT Contact: Len Makowski
Final report (1 MB)
Research Brief (330 KB)
Researchers conducted a life-cycle cost analysis that compared stone matrix asphalt overlays with conventional hot-mix asphalt overlays, taking into account required maintenance and performance. On low-volume asphalt pavements, researchers found that SMA overlays were more cost-effective (but not substantially) than HMA overlays. On moderate- to high-volume jointed reinforced concrete pavements, conventional HMA overlays were more cost-effective. However, because the SMA overlays studied were likely placed on more deteriorated pavements, they would be expected to have shorter service lives and higher life-cycle costs. Researchers recommend that designers select overlay materials on a case-by-case basis.

Title: Guidance, Parameters and Recommendations for Rubblized Pavements
Project ID: 0092-05-07
Publication Date: February 2007
Investigator: Harold Von Quintus, ERES Consultants
WisDOT Contact: Bob Arndorfer
Final report (1 MB)
Final report appendices (1.3 MB)
Research Brief (264 KB)
WisDOT regularly rubblizes portland cement concrete pavements prior to overlay with hot-mix asphalt. In this project, researchers sought to identify the factors that impact performance of rubblization projects. They found that HMA overlays of rubblized PCC in Wisconsin have matched or exceeded their design lives, with pavement structure age and overlay thickness being most the important variables affecting performance. Researchers developed a manual for designing and constructing rubblized PCC pavements that WisDOT can incorporate into its Facilities Development Manual. 

Title: Non-Nuclear Density Testing Devices and System to Measure In-place Asphalt Pavement Density
Project ID: 0092-05-10
Publication Date: January 2007
Investigator: Robert Schmitt, University of Wisconsin-Platteville 
WisDOT Contact: Len Makowski
Final report (1.4 MB)
Research Brief (209 KB)
Investigators evaluated non-nuclear density gauges for use in determining the in-place density of compacted asphalt pavements in Wisconsin. In field tests, the non-nuclear gauges produced consistently lower density readings than nuclear gauges. To offset these differences, investigators recommended that non-nuclear gauges be calibrated daily at each project site and that technicians take at least 30 readings within each lot to ensure acceptable confidence levels. Nuclear gauges will still be needed for calibration, but this research will help WisDOT minimize their use.

Title: Investigation of New Devices for use in Determining Mechanistic Properties and Performance
Project ID: 0092-03-15
Publication Date: April 2006
Investigator: Yusef Mehta, Rowan University
WisDOT contact: Len Makowski
Final report (824 KB)
Research Brief (255 KB)
The researchers studied methods for testing hot-mix asphalt materials to predict performance through mechanistic properties. They identified the creep and recovery test as the most promising technique. The test could be used in field settings to monitor asphalt mixtures during construction, allowing contractors to adjust mixtures in the field as necessary to optimize long-term pavement performance. Further research on creep and recovery is needed before implementation.

Title: Guidelines for the Surface Preparation/Rehabilitation of Existing Concrete and Asphaltic Pavements Prior to an Asphaltic Concrete Overlay
Project ID: 0092-04-05
Publication Date: August 2005 
Investigator: Haifang Wen, Bloom Consultants
WisDOT Contact: Len Makowski
Final report (2.9 MB)
Research Brief (402 KB)
Though a large proportion of Wisconsin paving projects are asphaltic overlays of concrete or asphalt pavements, the condition of the pavements to be overlaid and the methods for preparing surfaces vary widely. This can make for uneven performance and for difficulties in assessing life cycle costs. Researchers for this study developed guidelines for surface preparation prior to asphaltic overlay placement, dividing the guidelines according to the material to be overlaid (asphlatic or concrete). These guidelines form the basis of a consistent overlay design and construction policy, which will improve predictability in project budgeting if adopted by WisDOT.

Title: Development of Modulus-to-Temperature Relations for HMA Mixtures in Wisconsin
Project ID: 0092-03-14
Publication Date: November 2005 
Investigator: James Crovetti, Marquette University
WisDOT contact: Len Makowski 
Final report (876 KB)
Research Brief (513 KB)
This research resulted in development of a procedure for estimating in-place resilient modulus of HMA, regression equations to estimate resilient modulus at specific temperatures in the field, and a process for using climate data to develop estimated HMA resilient modulus values for each month for a given region. WisDOT pavement designers can use the methods developed in this study to predict mechanistic performance more accurately than current practices allow.

Title: Development of Rational Overlay Design Procedures for Flexible Pavements
Project ID: 0092-00-05
Publication Date: September 2005 
Investigator: James Crovetti, Marquette University
WisDOT contact: Len Makowski
Final report (688 KB)
Research Brief (219 KB)
This study resulted in recommendations for modifying WisDOT's overlay design procedures, including use of an effective structural number assessment procedure, pavement condition and surface deflection measures, and deflection testing. By implementing these recommendations, WisDOT will be able to create more technically sound overlays while providing a transition to the AASHTO mechanistic-empirical design guide.

Title: Development of Guidelines for PG Binder Selection for Wisconsin
Project ID: 0092-01-01
Publication Date: July 2005
Investigator: Hussain Bahia, University of Wisconsin-Madison
WisDOT Contact: Len Makowski
Final report (2.6 MB)
Research Brief (350 KB)
This project developed guidelines to help WisDOT narrow the range of possible asphalt binder grades to those that are most appropriate for Wisconsin roads and climates and that are readily available from regional refineries.

Title: Effects of Pavement Lift Thickness on Superpave Mix Permeability and Density
Project ID: 0092-02-14c
Publication Date: April 2005
Investigator: Jeffrey Russell, University of Wisconsin-Madison
WisDOT contact: Len Makowski
Final report (742 KB)
Research Brief (183 KB)
This research looked at the influence of pavement thickness and gradation, aggregate source, and nominal maximum size aggregate on the permeability and density of Wisconsin Superpave mixes.

Title: Using the Gyratory Compactor to Measure the Mechanical Stability of Asphalt Mixes
Project ID: 0092-01-02
Publication Date: January 2005
Investigator: Hussain Bahia, University of Wisconsin-Madison
WisDOT contact: Len Makowski
Final report (4.6 MB)
Research Brief (199 KB)
This study evaluated the effectiveness of using a simple shear plate accessory to the gyratory compactor to measure the mechanical stability of asphalt mixes in the laboratory.

Title: The Effect of Fine Aggregate Angularity, Asphalt Content and Performance Graded Asphalts on Hot-Mix Asphalt Performance
Project ID: 0092-45-98
Publication Date: January 2002
Investigator: Hussain Bahia, University of Wisconsin-Madison
WisDOT contact: Len Makowski
Final report (1.6 MB)
Research Brief (150 KB)
Investigators studied fine aggregate angularity and its potential interaction with asphalt content and performance grade as it pertains to rut resistance. They found that higher FAA values do not necessarily lead to better-performing pavements and that the effects of FAA on pavement performance are highly dependent on aggregate source.

Title: Evaluation of the Extent of HMA Moisture Damage in Wisconsin as it Relates to Pavement Performance
Project ID: 0092-01-03
Publication Date: January 2002
Investigator:  Hussain Bahia, University of Wisconsin-Madison
WisDOT contact: Len Makowski
Final report (1.2 MB)
Research Brief (202 KB)
This study examined the relationship of moisture test results to pavement performance and the cost-effectiveness of anti-stripping additives. Results supported the value of using anti-stripping additives but showed that the Tensile Strength Ratio test was not effective in determining when to use the additives.

Title: Determining a Temperature-Density Relationship after Completed Rolling of Hot Mix Asphalt
Project ID: 0092-00-06
Publication Date: January 2002
Investigator: Hussain Bahia, University of Wisconsin-Madison
WisDOT contact: Len Makowski
Final report (895 KB)
Research Brief (195 KB)
This study measured asphalt pavement densities on several construction projects after final rolling and then in the same location the following day when the pavement had cooled. Results indicated no significant difference between the two density measurements.  Parallel tests were conducted with laboratory samples of compacted asphalt. 

Title: Minimum Pavement Lift Thickness for Superpave Mixtures
Project ID: 0092-00-04
Publication Date: December 2001
Investigator: Hussain Bahia, University of Wisconsin-Madison
WisDOT contact: Len Makowski
Final report (1 MB)
Research Brief (577 KB)
This project examined the effect of lift thickness as it relates to the density of Superpave hot mix asphalt pavements. Both lab and field studies were included. In the field, lift thickness was varied to as thin as 1.25." The overall trend seen was that thickness had no effect on density and that thicker layers needed more roller passes to achieve density. There was a lack of correlation between lab and field results.

Title: Stone Matrix Asphalt: The Wisconsin Experience
Project ID: 0092-45-87
Publication Date: January 2002
WisDOT contact: Deb Bischoff
Final report (800 KB)
The objective of this study was to conduct a thorough evaluation of Stone Matrix Asphalt (SMA) which consists of a large coarse aggregate content, fine aggregate, high filler content,  asphalt cement (with or without a modifier) and usually a cellulose or mineral fiber. Six projects, each with six test sections, were constructed over a period of three years, ending in 1994, and evaluated for ease of construction and for performance.

Research in progress

See all quarterly reports for in-progress asphalt pavement research on the WHRP Web site

Title: Recycling Rubber Modified Asphalt
Project ID: 0092-45-52
WisDOT contact: Deb Bischoff
Quarterly report (8 KB)
The objective of this study is to determine the recyclability of asphalt pavements containing tire rubber (rubberized asphalt). An assessment will be made of impacts on design, construction, performance, cost and the environment.

 

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Last modified: July 14, 2008