Pavement Underdrain to Achieve Longer Life Pavement Structure

Drainage as the key to pavement performance has been suggested since the early design of modern pavement structures. In fact, the three parameters for pavement performance are drainage, drainage and drainage. Drainage is so important to the performance of pavement that many state DOTs mandate a pavement underdrain system for routes with medium to high truck traffic. In the current evolution of pavement underdrain design, the speed of water removal from the soil foundation is the key issue. In a recent field investigation, some pavement sections with an underdrain system are not immune to pavement structural deterioration. It was determined that proper construction of the underdrain system is the key to ensuring that water will not accumulate in the soil foundation. This presentation will explore the requirements, design, construction, and performance of the underdrain system

Correlation between Resilient Modulus (M\u3csub\u3eR\u3c/sub\u3e) of Soil, Light Weight Deflectometer (LWD), and Falling Weight Deflectometer (FWD)

INDOT adopted the Mechanistic-Empirical Pavement Design Guide (MEPDG) beginning January 1, 2009, which is based on the FHWA Long Term Pavement Performance (LTTP) field study. The resilient modulus of the soil, MR, is required to implement the new design guide, as well as the pavement input parameters. The soil resilient modulus test requires special, expensive, equipment, significant time investment and effort, which has led researchers to develop MR prediction models and alternative methods to estimate the resilient modulus using non-destructive tests such as Falling Weight Deflectometer, FWD, Light Weight Deflectometer, LWD, and Dynamic Cone Penetrometer, DCP. The objectives of the project are geared toward a practical approach for pavement design procedures to effectively determine the soil resilient modulus for rehabilitation projects, targeting specifically untreated subgrade soils type A-6 and A-7-6. A total of four sites in Indiana were selected to conduct FWD, LWD, and DCP tests, as well as resilient modulus tests in the laboratory. In addition to the output from the four sites, additional data were collected from the data repository of INDOT which has geotechnical and pavement information. Extensive analysis and comparisons were done in an attempt at establishing relationships between the field tests and the laboratory results. The study showed the following: (1) high quality FWD tests conducted on top of the pavement can be used to estimate the subgrade MR, as long as site conditions and pavement layers thickness are well known; (2) the results of FWD tests on top of the subgrade are not reliable, as they are affected by the low confinement of the soils; and (3) LWD and DCP tests can be used to provide and assessment of the quality and uniformity of the subgrade, but do not provide reliable estimates of the stiffness of the subgrade

Structural Evaluation of Full-Depth Flexible Pavement Using APT

The fundamentals of rutting behavior for thin full-depth flexible pavements (i.e., asphalt thickness less than 12 inches) are investigated in this study. The scope incorporates an experimental study using full-scale Accelerated Pavement Tests (APTs) to monitor the evolution of each pavement structural layer\u27s transverse profiles. The findings were then employed to verify the local rutting model coefficients used in the current pavement design method, the Mechanistic-Empirical Pavement Design Guide (MEPDG). Four APT sections were constructed using two thin typical pavement structures (seven-and ten-inches thick) and two types of surface course material (dense-graded and SMA). A mid-depth rut monitoring and automated laser profile systems were designed to reconstruct the transverse profiles at each pavement layer interface throughout the process of accelerated pavement deterioration that is produced during the APT. The contributions of each pavement structural layer to rutting and the evolution of layer deformation were derived. This study found that the permanent deformation within full-depth asphalt concrete significantly depends upon the pavement thickness. However, once the pavement reaches sufficient thickness (more than 12.5 inches), increasing the thickness does not significantly affect the permanent deformation. Additionally, for thin full-depth asphalt pavements with a dense-graded Hot Mix Asphalt (HMA) surface course, most pavement rutting is caused by the deformation of the asphalt concrete, with about half the rutting amount observed within the top four inches of the pavement layers. However, for thin full-depth asphalt pavements with an SMA surface course, most pavement rutting comes from the closet sublayer to the surface, i.e., the intermediate layer. The accuracy of the MEPDG’s prediction models for thin full-depth asphalt pavement was evaluated using some statistical parameters, including bias, the sum of squared error, and the standard error of estimates between the predicted and actual measurements. Based on the statistical analysis (at the 95% confidence level), no significant difference was found between the version 2.3-predicted and measured rutting of total asphalt concrete layer and subgrade for thick and thin pavements

Evaluation of Zero Velocity Deicer Spreader and Salt Spreader

Increasing traffic volumes and declining resources have led to a need for innovative winter maintenance strategies, techniques, equipment and materials while not sacrificing the safety of the traveling public. Any reduction of salt usage will ease fund for other maintenance operations while minimizing salt runoff on surface and ground waters and effect of road salt on roadside vegetation. In the past, conventional spreaders have been designed for sand and are generally incapable of metering the lower, more precise amount of salt desired. The use of materials in solid form demands critical timing of the application to minimize loss of the material by being blown off the road by traffic, especially by high speed and commercial vehicles. Further loss of a straight solid salt can occur during application with conventional spreaders because of the particles bouncing off the pavement. Advancements in the design of zero velocity spreaders have enabled the placement of solid chemicals on the pavement with minimum bounce. The basic principle of the zero velocity spreader is rather simple. The zero velocity spreader ejects salt particles at zero velocity relative to the roadway. With this principle, salt particles are “placed” to the intended area on the roadway and a lot less to the area outside the roadway. Based on the tests, the Zero Velocity Systems will give excellent performance with a large number of cost savings due to the accurate placement of salt particles on the roadway. However, on the slower truck speed, a modified system such as the Y system or Muncie system, can give a satisfactory result as well

Best Practices for Bridge Deck Overlays

This presentation discusses recent research regarding alternative bridge deck overlay methods and best practices associated with their use

Pavement Rehabilitation Options in Indiana for INDOT

Many pavement rehabilitation options are now available to maintain the function and structure of a pavement section, and pavement engineers can choose an option that is suitable for the existing pavement condition. Many agencies today use traditional pavement rehabilitation techniques such as patching, overlay, and mill and fill. Recent developments in materials and construction have made available new rehabilitation options that are not only cost effective but also increase the use of recycled materials. This presentation will feature hot-in-place recycling, cold-in-place recycling, and full-depth reclamation techniques used successfully with recently rehabilitated pavement sections in Indiana

Pavement Rehabilitation Options in Indiana

Many pavement rehabilitation options are now available to maintain the function and structure of a pavement section, and pavement engineers can choose an option that is suitable for the existing pavement condition. Many agencies today use traditional pavement rehabilitation techniques such as patching, overlay, and mill and fill. Recent developments in materials and construction have made available new rehabilitation options that are not only cost effective but also increase the use of recycled materials. This presentation will feature hot-in-place recycling, cold-in-place recycling, and full-depth reclamation techniques used successfully with recently rehabilitated pavement sections in Indiana

Analysis and Determination of Axle Load Spectra and Traffic Input for the Mechanistic-Empirical Pavement Design Guide

The values of equivalent single axle loads (ESAL) have been used to represent the vehicle loads in pavement design. To improve the pavement design procedures, a new method, called the Mechanistic-Empirical Pavement Design Guide (MEPDG), has been developed to use the axle load spectra to represent the vehicle loads in pavement design. These spectra represent the percentage of the total axle applications within each load interval for single, tandem, tridem, and quad axles. Using axle load spectra as the traffic input, the MEPDG method is able to analyze the impacts of varying traffic loads on pavement and provide an optimal pavement structure design. In addition, the new method can be used to analyze the effects of materials and the impacts of seasons, to compare rehabilitation strategies, and to perform forensic analyses of pavement conditions. The MEPDG utilizes mechanistic-empirical approaches to realistically characterize inservice pavements and allows the full integration of vehicular traffic loadings, climatic features, soil characteristics, and paving materials properties into the detailed analysis of pavement structural behaviors and the resulting pavement performance. In order to provide the traffic data input required by the MEPDG, the Indiana Department of Transportation (INDOT) made an effort to obtain truck traffic information from the traffic data collected through weigh-in-motion (WIM) stations. This study was conducted to create the truck traffic spectra and other traffic inputs for INDOT to implement the new pavement design method. Furthermore, the INDOT AADT data were used in this study to analyze the spatial distributions of the traffic volumes in Indiana and to obtain the spatial distributions of traffic volumes