Current Research in the IMP Group

1:Rutting Evaluation of Full-Depth Flexible Pavement Using Accelerated Pavement Testing

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   This project developed a new method to calibrate the rutting transfer functions in the Mechanistic-Empirical Pavement Design Guide (MEPDG) using accelerated pavement testing (APT) techniques, the new method has improved the MEPDG’s prediction performance by 70%.
   A Mid-depth Profile Monitoring System (MPMS) was also developed to investigate the rutting behavior of flexible pavements. The MPMS is able to capture the pavement layer-wise deformation with millimeter accuracy.





2: Sensitivity Analysis of Design Inputs for Mechanistic-Empirical Pavement Design Guide (MEPDG)on Flexible Pavements for Low-Volume Roads

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   The Mechanistic Empirical Pavement Design Guide (MEPDG) was developed to help connect the design theories with predicted pavement response. It is an improvement to the 1993 AASHTO design. Inputs for the MEPDG include climate data, local material properties, traffic loads, etc. Since the MEPDG involve numerous input parameters, input levels are utilized which can be classified into 3 levels. Level 1 demands the highest accuracy of the inputs while level 3 requires typical values. To be able to implement the MEPDG efficiently, it is necessary to review existing data for input parameters, perform a sensitivity analysis, and calibrate and validate the model in order to precisely relate predicted pavement distresses to local conditions and design criteria. But building a database for calibration and validation requires a number of field tests which can be a very strenuous task.
   The main interest of this study is to perform a sensitivity analysis to determine the sensitivity of each input parameter for the MEPDG based on local conditions in Indiana. Since gathering data for input parameters can be very demanding, the results of this study will help with the implementation of the MEPDG. Data collecting process can be done more effectively by directing the effort to the most sensitivity design inputs, thus reducing costs of pavement design and construction.





3: Method for Quality Control Assessment of Statewide Pavement Surface Evaluation Ratings Performed by Local Agencies

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   Pavement surface evaluation ratings (PASER) assigns roads a condition rating through means of an estimated visual distress survey. Ratings range from 10 to 1, with a rating of 10 being a new pavement and a rating of 1 being a failed pavement. The PASER method takes less training, time, and resources to obtain pavement condition data and is therefore a practical option for budget-minded local agencies. . In 2016, 312 local agencies in Indiana including cities, counties, and towns took advantage of the funding match offered under House Enrolled Act 1001 and submitted pavement condition data for over 290,000 pavement segments representing 76 percent of the statewide local network. Considering the subjective nature of visual distress surveys, the objective of this research is to develop a statistically based quality control (QC) assessment method that can be applied to assess the quality of statewide local agency PASER ratings. This will be accomplished by performing PASER ratings on a statistically representative subsample of local agency PASER-rated pavement segments, which will then be statistically evaluated using four agreement definitions: complete agreement, within one rating agreement, within two ratings agreement, and within maintenance category agreement.





4: Quantifying Asphalt Emulsion-Based Chip Seal Curing Times Using Electrical Resistance Measurements

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Mountain View

   The quality and performance of chip seal treatments during their service life are driven primarily by the construction phase. The objective of this research is to fully implement an electrical measurement technique that can consistently determine when a chip seal system has sufficiently cured and, therefore, decide when a chip seal can safely be broomed and opened to unrestricted traffic. Electrical measurement techniques can provide a rapid, nondestructive indication of the amount of curing that has occurred in a chip seal.





5: Investigating the Potential to Use Phase Change Materials (PCM) to Store Heat in Asphalt and Layered Pavement Thereby Reducing the Need for Anti-Icing

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   The removal of snow and ice from the transportation infrastructure is costly. Common practices for removing them from the infrastructure include the use of snowplowing, deicing chemicals or both. These methods are costly, have environmental impact, and can be labor intensive. This project examines the role that phase change materials (PCM) may have in storing heat in asphalt pavements in an effort to delay and reduce the decrease in pavement surface temperature.





6: Investigating the Need for a Drainage Layer in Flexible Pavements

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   Moisture intrusion can have a catastrophic effect on flexible pavement performance. As such, it is important to remove moisture as quickly as possible from flexible pavements, especially to avoid allowing moisture into the pavement subgrade. As the subgrade moisture content increases, so will the likelihood of pavement failure as the subgrade softens or frost action occurs. Given the damage potential of moisture intrusion, in the 1990’s the Indiana Department of Transportation adopted a flexible pavement drainage system that includes an open-graded asphalt mixture as a drainage layer connected to edge drain collector pipes in order to remove moisture from the pavement system. However, over the intervening two decades, flexible pavement materials and construction practices have changed dramatically. Today, in-place field densities achieved during construction make asphalt mixtures less susceptible to moisture intrusion than their 1990’s counterparts.
   Given the challenges involved with producing and placing open-graded asphalt mixtures used for drainage layers, their increased cost, the changes to the materials and construction specifications, and their reduced overall structure capacity, the objectives of this research were to evaluate the effectiveness of flexible pavement drainage systems produced using currently specified materials and construction practices and to determine, given the newer specifications, if the drainage system is still needed in flexible pavements.
   Preliminary finite element modeling results indicate lower subgrade saturation in flexible pavements containing a drainage system, while the subgrade remains fully saturated for those without a drainage system.
   Coupled Diffusion/Deformation Analysis will be done to investigate the mechanical performance of flexible pavements drainage system.





7: Soybean-based Asphalt Rejuvenator (Phase II)

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   This research focuses on laboratory mixture evaluations of RAP combined with soybean-based rejuvenator. Previous work has already shown that soybean-based products can be readily blended with asphalt binders and soften the binders. In phase I , an investigation on a soybean-based product, SAS is reported, specifically for its abilities to rejuvenate aged asphalt binders. Phase II research quantifies how well the rejuvenator works on the asphalt binder when it is added directly to the RAP. In practice, RAP is milled from the road and then re-incorporated into new asphalt mixtures. The goal is to develop a feasible guide to instruct how to use a soybean-based rejuvenator in RAP recycling in road construction.