New research is coming! The 5 National Road Research Alliance (NRRA) teams brainstormed ideas, and budgets, for the upcoming years and the projects were finalized by the Executive Committee early in 2019:
⢠Test sections that will be constructed at MnROAD
⢠Test sections that will be constructed elsewhere
⢠Reports that synthesize current best practices.
Here is the research that the alliance will pursue for years 4 and 5 of this pooled-fund agreement:
1 – PAVEMENT MAINTENANCE TEAM:
Spray-on Rejuvenator Synthesis: A report that will be a synthesis of field projects constructed to evaluate spray-on rejuvenators, by NRRA members, National Center for Asphalt Technology (NCAT), National Cooperative Highway Research Program (NCHRP), Minnesota (MN) cities and counties, and others. It will also include all recent research projects by MoDOT with the ARA. The final report should read as a work plan for the rejuvenator test sections. It will include products to test, tests to run, frequencies, etc.
Spray-on Rejuvenator Test Sections: A very detailed study of spray applied rejuvenators on a newer HMA pavement. Testing will include friction, pavement marking reflectivity, and other tests to study the effect of these products.
Service Life Enhancement of Substrates Overlaid with Thin Overlays (UTWBC, Chip Seals & Microsurfacing) for each state: Using the pavement management data from 8 NRRA member states:
⢠Determine the service lives for the 3 nonstructural overlays
⢠Deduce service-life enhancements that these nonstructural overlays contribute to the identified pavement types where the overlays were placed
This research identifies and focuses on the following conventional non-structural overlays:
⢠Chip seal
⢠Ultrathin bonded wearing course (UTWBC)
⢠Microsurfacing, flexible substrates
2 – INTELLIGENT CONSTRUCTION TECHNOLOGY TEAM:
Evaluation of Levels 3-4 Intelligent Compaction Measurement Values (ICMV) for Soils Subgrade and Aggregate Sublease CompactionâThe objective of this project is to:
⢠Evaluate Level 3/4 ICMV systems against Level 1/2 ICMV systems for soils and base compaction
⢠Develop a blue print for future certification procedures of IC. Field tests will be done though the FHWA
Support Importing, Viewing and Analysis of Dielectric Constant Data in VetaâThis project will add the following features to “Veta” Software (Standardized intelligent construction data management (ICDM) software that:Â Stores, maps and analyzes geospatial data resulting from intelligent compaction, thermal profiling and spot test data (e.g., density, moisture); Performs standardized data processing, analysis and reporting to provide Project summary results quickly; Provides statistics, histograms, correlations for these measurements, document coverage area and evaluate the uniformity of compaction and surface temperature measurements as part of the Project quality control operations):
⢠Import GPR dielectric constants data files in the AASHTO Intelligent Construction Data Standard Format
⢠Calculate the predicted air voids using this data
⢠Add data maps, filters and analyses for dielectric constants data and predicted air voids
HD and VHD Seismic Approaches for Roadway Evaluation âThe objective of this project is to:
⢠Further verify that this technology can accurately measure the pavement layer (later phases of the work could focus on the base and subbase layers)
⢠Attempt to develop a means of taking these measurements while continuously drivingÂ
3 – RIGID TEAM:
Construction Report for Jointless FRC Roundabout in MinnesotaâThis research will generate a construction report to document the mix design usedâalong with details about production and placement of the FRC mixture. This project will also monitor and document field performance for the next 3 years.
Incorporate Joint Faulting Model Into BCOA-MEâA research project that will incorporate a faulting model into the existing BCOA-ME program used to design bonded concrete overlays on top of asphalt pavement.
Engineered Dowel and Tie Bars combined with LTPP SPS-2 Determination of Causes for Cracking Over Dowel BarsâThe goal of this project is to identify the cause(s) and contributing factors of concrete pavement cracking and delaminating along the plane of dowel and tie bars. This will involve a comprehensive literature review, assessment and summary of instances of this delamination occurring nationally.
4 – FLEXIBLE TEAM:
Mix Rejuvenator Synthesis (Phase-1)âThis synthesis will summarize the experiences that each NRRA member State has had regarding asphalt mixture rejuvenators, and is intended to share implementation projects to facilitate transfer of knowledge and provide guidance to NRRA Mix Rejuvenator Test Sections (Phase II)
Mix Rejuvenator Test Sections (Phase-II)âTest sections with different mix rejuvenator products will be constructed during summer 2019 in central Minnesota and long-term field performance will be monitored.
5 – GEOTECH TEAM:
Mechanistic Load Restriction Decision Platform for Pavement Systems Prone to Moisture VariationsâA load-restriction-decision platform will be developed to reliably evaluate pavement bearing capacity and performance. The final product will be a user-friendly tool that will help pavement engineers assess traffic impacts during and after periods of excessive moisture caused by extreme weather or seasonal variations.
Environmental Impacts on the Performance of Pavement Foundation LayersâSeasonal freeze-thaw weakening and changes in saturation due to environmental fluctuations have a significant effect on pavement foundation strength and performance. This project will develop a model to predict frozen soil depth and duration using precipitation, solar radiation, and temperature from existing MnROAD measurements and then estimate the strength and performance of pavement foundation layers subjected to freeze-thaw cycles.
Permeability of Base Aggregate and SandâProject that will quantitatively assess the permeability of granular materials from aggregate base to sand using existing methods validated by a very limited number of laboratory tests. A simple predictive tool will be developed to estimate field permeability using the grain size distribution, crushing percentage, fines content, angularity, and material type.
Improve Material Inputs into Mechanistic Design Properties for Reclaimed HMA RoadwaysâThe stiffness, strength, gradation, and hydraulic conductivity of reclaimed asphalt pavement and recycled concrete aggregate used as base and subbase will be collected from the NRRA member states and additional literature. Field and laboratory tests, construction specifications, and pavement performance will be used to recommend input for mechanistic design after a sensitivity analysis has been completed.
For all of the details of this upcoming research, please go to: http://www.dot.state.mn.us/mnroad/nrra/newsletter/currentissue.html?utm_content=&utm_medium=email&utm_name=&utm_source=govdelivery&utm_term=#upcoming