People desire smooth, quiet, and safe pavements. To encourage smooth pavements, we need to quantify the effects of other important pavement performance parameters on ride. These parameters include texture, noise, and friction. An understanding of the interaction of texture and ride is still very rudimentary. In 2002 the Mn/DOT Concrete Engineering Unit and the Concrete Pavers Association of Minnesota created a test section on TH 212 at Bird Island to study the effects of texture and joints in pavement smoothness. The results showed that profile index was affected by texture and joints. However, data is so far insufficient to define a global correlation between texture values and their effect on ride, and the results obtained for the effects of joints on ride were not conclusive because of unanticipated construction issues. One option is for rehabilitating Portland cement concrete pavements without the need to restore structural capacity is to diamond grind the surface. This process removes much of the pavement roughness and restores texture and friction. Many variables play into the grinding operation, such as blade spacing, depth of cut, kerf configuration, etc. There is a need for a standardized specification for diamond grinding. These parameters affect and govern the preponderant frequencies that cause noise when such frequencies are not randomized. Power spectrum density analysis of results obtained in the Bird Island Test section as well as profilometer-generated roughness showed that diamond grinding did improve the ride. The resulting texture and noise were not measured until 2005 when the FHWA PSC study team measured the site. Minor changes in the geometry of diamond grinding equipment tremendously affect the friction and noise performance, but the optimum geometry is still unknown. This research item is in harmony with the CPTP track 4 of the CPTP road map. This track seeks better understanding of concrete pavement surface characteristics and provides tools for engineers to help meet pre-determined requirements for ride quality, quietness, safety against hydroplaning and splash/spray, and durability. Related studies include: . TPF 962: Pavement Surface Properties Consortium: A Research Program (Virginia) . NCHRP 1-44: Measuring Tire-Pavement Noise at the Source (Illingworth & Rodkin, Inc.) . NCHRP 1-43: Guide for Pavement Friction (ERES) . TPF 956: PCC Surface Characteristics: Tire -Pavement Noise Program Part 3 - Innovative Solutions /Current Practices (Iowa State) . NCHRP 10-67: Texturing of Concrete Pavements (ERES) . Fundamentals of Tire/Road Interaction Noise (Purdue University) The TPF 962 study mentioned above is meant to serve mainly the Eastern United States. The research proposed in this work could be seen as a parallel research study for the Upper Midwest. MnROAD provides a unique opportunity to measure surface characteristics of a variety of PCC pavements with various pieces of equipment in a safe and controlled environment. This research also serves as an extension/validation of several of the current NCHRP studies. The findings relating to measuring noise and frictional characteristics could be validated with a field study at MnROAD. The current Purdue University study is expected to provide recommendations on pavement surface textures that can provide desirable levels of safety and reduction in noise levels. Along with that may come some recommendations on grinding operations so as to mitigate noise issues. The research proposed in this pooled fund study would serve to validate the recommendations from Purdue. The use of power spectrum density analysis to better characterize tire-pavement noise is also a unique feature to this project. As public demand for quieter pavements increase this study can lead to improved methods for modifying existing PCC pavements to make them quieter without sacrificing friction.

Research findings will enable Mn/DOT to specify friction, ride, and texture ranges of values that will optimize quietness, ride, texture and friction in program delivery. It will reduce the incidence of uncomfortable ride, hydroplaning, and obnoxious whines. The average road user benefits from the results of this study. Research outcomes will facilitate a family of curves and algorithms that will address the optimization for giving good friction, which unfortunately was interpreted by profilometers as pavement roughness as well as noise and friction. We will have a prediction of noise level based on the grinding techniques. The project will provide data for optimization of pavement quietness, friction, texture and ride. We will be in a better position to improve our diamond grinding and texture specification if necessary. It will address the question as to what degree of total noise is generated by tire-pavement interaction. Monitored over time, performance versus time characteristics will be obtained for various grinding techniques. This pooled fund study is strictly to perform the surface characteristics research on rehabilitated test sections at MnROAD, and its funding will come from Mn/DOT and other participating states. The funding for the rehabilitation of the test sections will be obtained separately from Mn/DOT and other partners.

A 3-mile concrete section of old westbound I-94 runs parallel to the Mainline at MnROAD. It is possible to use this entire stretch for applying different surface rehabilitation techniques for the purposes of this study. Mn/DOT plans to create contiguous test sections of each of the following rehabilitation techniques: . Diamond grinding (several variations) . Grooving . Exposed aggregate . Acid etching This project is expected to consist of the following tasks: . Work Plan: The work plan for this pooled fund study will be developed by the participating organizations. . Special Testing & Monitoring: A continuous testing and monitoring program will include: o Profile runs with the single laser LWP on all strips. o Profile runs with the multi laser LWP on all strips. o Profile runs with the Australian Walking Profiler (ARRB WP) on textured and un-textured strips. o Texture measurements at every 5-ft on the textured (each side) and the untextured strips with circular texture meter. o Friction measurements with the FHWA skid trailer on the textured strips compared to the un-textured strips. o Sound measurements (tire pavement interaction) on the textured and untextured strips with the NCAT trailer, close proximity measurements, or roadside measurements. . Noise Modeling & Validation: Apply the findings of this study to current noise modeling software (TNM, MINNOISE, etc.). . Pooled Fund Travel: Money for each state to travel to discuss the progress of the study. . Data Analysis & Reports: Work done under a research contract will develop interim and final reports that document the findings of this study.

Mn/DOT along with other participating states are asked to contribute $15,000 per year for 5 years to fund the research proposed in this pooled fund study. The Minnesota Department of Transportation (as the lead agency) along with other partners will provide other funding outside of this pooled fund study to rehabilitate the concrete pavement test sections with regard to certain surface characteristics.