Protocols for Network-Level Macrotexture Measurement (2021) / Chapter Skim
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3 The various components of pavement surface texture have a high influence on vehicle-road interactions. In particular, macrotexture features contribute to pavement friction, tire-pavement noise, splash and spray, and rolling resistance.
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4 Protocols for Network-Level Macrotexture Measurement 2. Develop improved methods for network-level macrotexture measurement that address these factors and parameters; and 3.
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Introduction 5 in Figure 2) are defined as "a continuous 2D sample along a [horizontal]
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6 Protocols for Network-Level Macrotexture Measurement • ISO 13473-1 (1997, updated 2019)
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Macrotexture Method Specification Type Speed Equipment Cost Texture Parameter * Technology Reference Volumetric Sand Patch E-965 Volumetric N/A < $100 MTD Manual Current Standard Grease Patch NASA *
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8 Protocols for Network-Level Macrotexture Measurement One advantage of these 3D approaches is that they allow for the computation of area-based macrotexture characterization parameters; however, they remain stationary methods and therefore require traffic control. To date, efforts to use these 3D techniques for high-speed measurements have not been proven.
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Introduction 9 less damaging than steel (e.g., aluminum, ceramics) have been proposed.
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10 Protocols for Network-Level Macrotexture Measurement friction measurements, due primarily to issues arising from the dependency of various contact methods on the test tire properties (Ferne 2015)
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Introduction 11 Pavement Surface Properties Consortium Experiments In the United States, the Pavement Surface Properties Consortium has pooled-funds to conduct periodic equipment comparisons since 2007 (e.g., TPF-5[141]
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12 Protocols for Network-Level Macrotexture Measurement The MPD is based on two peaks in the measured macrotexture profile that determines the (free) area below those two peaks.
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Introduction 13 Other lesser-known methods of texture characterization are based on pavement surface classifi cation systems. The Nakkel (1973)
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14 Protocols for Network-Level Macrotexture Measurement tended to overestimate a surface's ability to evacuate water, as shown in Figure 7. Correlation to friction and tire-pavement noise were also improved using this parameter.
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Introduction 15 In addition, the orientation of the texture is also important; asphalt concrete surfaces typically provide a relatively neutral macrotexture, which means the predominant features are neither upward-oriented asperities nor valleys between them (Flintsch et al.
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16 Protocols for Network-Level Macrotexture Measurement Operational and Environmental Factors Affecting Data Collection The following operational and environmental factors that may affect the various macrotexture parameters were identified: • Speed and acceleration: Macrotexture lasers record data in the time domain, and varying the speed above or below a specified speed will result in either less data or more data being collected over the same distance. The problem is amplified in camera systems, as shutter speed can also significantly affect the accuracy of the data gathered (El Gendy and Shalaby 2007; Huang et al.
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Introduction 17 or sensor packages. Laser ranging equipment should be calibrated according to the manufacturer's directions.
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18 Protocols for Network-Level Macrotexture Measurement 1.3 Survey of State Highway Agencies A survey to determine the state of the practice on measuring macrotexture and its use for network-level pavement management by state highway agencies was developed and conducted using Virginia Tech's survey website. The invitation to participate in the survey (via transmittal letter)
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Introduction 19 The responses to the questions were considered in determining good practices on macrotexture data collection, appropriate processing approaches, and the most suitable macrotexture characterization parameters. Some gaps in common understanding concerning what macrotexture is and how it relates to network management, were also revealed in responses.
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20 Protocols for Network-Level Macrotexture Measurement • Lack of use of macrotexture data in favor of microtexture information provided by friction testing (limited resources are dedicated to friction testing instead) ; and • Pavement features such as tining are considered to provide adequate macrotexture.
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Introduction 21 • Macrotexture data is collected but only for projects such as applications of High-Friction Courses, where a macrotexture parameter is used for project acceptance. 1.3.3 Equipment Used to Collect Macrotexture Data Table 2 summarizes the equipment used by responding states to collect macrotexture data.
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22 Protocols for Network-Level Macrotexture Measurement measurements (i.e., as a screening tool for problem areas where macrotexture is low and friction demand is high) , for safety reasons (i.e., at specific locations in response to incidents)
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Introduction 23 level (one state)
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