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Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements
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Original Research Paper
Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements Q1
Shuo Li*, Dwayne Harris, Tim Wells Division of Research and Development, Indiana Department of Transportation, West Lafayette, IN 47906, USA
article info
abstract
Article history:
Recently, diamond grinding has gained increasing attention as pavement preservation
Available online xxx
treatment to restore desired surface characteristics, particularly friction. Compared to other pavement preservation treatments such as surface overlays and high friction surface treatments, diamond grinding may cost less, save construction time, or require minimum
Keywords:
maintenance. Diamond grinding produces longitudinal, continuous, and line-type texture
Concrete pavement
that contains corrugations with evenly spaced ridges. The improved surface texture will
Asphalt pavement
immediately enhance pavement surface friction and reduce the possibility of hydroplaning
Surface friction
in rainy weather. However, little information has been documented on the texture charac-
Diamond-grinding
teristics and long-term friction performance of diamond-ground pavements. A field evalu-
Macrotexture
ation was conducted to examine the surface texture and friction characteristics in diamond-
Microtexture
ground concrete and asphalt pavements by the authors. Five pavement test sections, including two diamond-ground concrete pavements, one diamond-ground concrete bridge deck, one diamond-ground asphalt pavement, and one transversely tined concrete pavement, were selected for evaluation. Laser scanner testing was performed to capture both macro and microtexture profiles. Locked wheel testing was performed to measure the friction numbers. The test results were examined and compared so as to evaluate two performances, after construction and long-term friction performance of diamond-ground pavements. It was found that longitudinal diamond grinding can provide durable, satisfactory surface friction performance for both concrete and asphalt pavements. © 2016 Periodical Offices of Chang'an University. Production and hosting by Elsevier B.V. on behalf of Owner. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1.
Introduction
Diamond grinding is a widely accepted practice to remove bumps and rectify surface defects on concrete pavements. It has been effectively used as part of concrete pavement restoration (CPR) since 1965 (ACPA, 2006; Caltrans, 2005). A
study surveyed a total of 76 diamond-ground concrete pavements from 9 states and found that the average life of a typical diamond-ground concrete pavement was about 14 years (Rao et al., 1999). It was also found that after diamond grinding, the pavement surface texture increased, and skid resistance improved considerably and the ground surfaces could last for 8e15 years. Although diamond grinding has been mainly
* Corresponding author. Tel.: þ1 765 463 1521, Fax: þ1 765 497 1665. E-mail addresses: [email protected] (S. Li), [email protected] (D. Harris), [email protected] (T. Wells). Peer review under responsibility of Periodical Offices of Chang'an University. http://dx.doi.org/10.1016/j.jtte.2016.08.001 2095-7564/© 2016 Periodical Offices of Chang'an University. Production and hosting by Elsevier B.V. on behalf of Owner. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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used to correct pavement profile, it has also found other methods, such as restoring pavement cross-sections with rutting greater than 13 mm (NDOR, 2002). To date, the identified advantages of diamond grinding include better ride quality, enhanced safety, quieter travel surface, extended service life, and reduced rehabilitation costs. Compared to other pavement preservation treatments such as overlays and high friction surface treatments, diamond grinding may cost less, save construction time, and produce minimum traffic interruption during construction. Diamond grinding also allows treating local problems and small areas. In addition, diamond grinding always produces an immediate increase in surface friction regardless of the effect of existing pavement and grinding operation. Consequently, diamond grinding has gained increasing attention as pavement preservation treatment to restore desired surface characteristics such as ride, noise, friction, and drainage on existing pavements. The International Grooving and Grinding Association (IGGA) has developed guide specifications for use of diamond grinding in three different operations, city streets, asphalt pavements, and pavement preservation (IGGA, 2014a, 2014b, 2014c). Federal Highway Administration (FHWA) has also provided requirements for diamond grinding for concrete pavement preservation (FHWA, 2005). Although diamond grindings in different operations may have a different purpose, i.e., to provide desired surface characteristics or to eliminate surface defects, diamond grindings in most operations follow similar procedures so as to provide longitudinal and continuous diamond grinding on pavements. In short, diamond grinding will inevitably restore surface friction characteristics through providing line-type texture that contains corrugations with evenly spaced ridges. The immediate result is the improved surface texture that will ultimately enhance pavement surface friction and reduce the possibility of hydroplaning in rainy weather. However, little information has been documented on the texture characteristics and long-term friction performance of diamond-ground pavements. Wet pavement friction is dominated by both surface macrotexture and microtexture (Kummer and Meyer, 1967; PIARC, 1987). Macrotexture provides channels for removal of water and reduces dynamic hydroplaning development (Gallaway et al., 1979; TRB, 1972). Microtexture punctures and drains the viscous water film between tire and pavement reducing the viscous hydroplaning development. Good microtexture reduces the likelihood of hydroplaning development (Browne, 1975; Ong et al., 2005). Also, microtexture may play an important role in reduction of dry pavement skidding accident. In reality, lanedeparture crashes account for 53% of all roadway fatalities (Nelson et al., 2011). The Indiana crash data also suggests that
during summer time, up to 88% of lane-departure crashes occur on dry pavements (ISP, 2012). Recently, diamond grinding has been used in Indiana on different pavements, including concrete pavements, asphalt pavements, and bridge decks. This paper documents the texture and friction test data and analysis results on these diamond-ground pavements. Such information will be useful to pavement engineers in better understanding the long-term friction performance and the proper use of diamond grinding in pavement and bridge deck preservations.
2.
Test sections and field tests
2.1.
Test sections
In order to examine the texture and friction characteristics of longitudinally diamond-ground hot mix asphalt (HMA) and Portland cement concrete (PCC) pavements, a total of five pavement test sections, four diamond-ground test sections and one transversely tined test section, as shown in Table 1, were selected for field testing and evaluation. The selection of these five test sections was based on pavement type, purpose of grinding, and performance comparison. The test section on SR-162 was classified as minor arterial and diamond grinding was used to re-profile the surface of new asphalt pavement. The test section on US-24 consisted of two lanes in each direction, and was classified as rural expressway. The pavement was newly constructed concrete pavement. Diamond grinding was completed to remove localized bumps before opening to traffic. The test section on US-50, consisting of two lanes in each direction, was classified as principal arterial in urban area. This section has several signalized intersections and the purpose of diamond grinding was to improve surface smoothness and friction of the new concrete pavement, particularly on intersection approaches. The diamond-ground bridge deck is located on I-80 in the north of Indiana and diamond grinding was used solely to restore polished deck surface. All of the above four test sections have high traffic volumes. In particular, the section on US-50 and the bridge deck on I-80 have heavy truck traffic. The friction track is part of the test track constructed by the Indiana Department of Transportation (INDOT) for validating friction test system and is not to the public. Although IGGA has developed specifications for conventional diamond grinding of city streets, diamond grinding asphalts, and diamond grinding for pavement preservation, respectively. These three specifications are aimed at providing the same final surface finish, i.e., longitudinal, corduroy-type texture with ridge peaks approximately 1.5e4.8 mm above the grooves. In the FHWA diamond grinding checklist for concrete
Table 1 e General information on selected pavement test sections. Road SR-162 US-24 US-50 I-80 Friction track
Classification
Pavement type
Grinding year
AADT
Truck traffic
Minor arterial Rural expressway Principal arterial Interstate N.A.
HMA PCC PCC PCC deck Tined PCC
2008 2012 2008 2013 N.A.
5095 8757 33,143 25,932 N.A.
9.6% 36.6% 5.7% 24.4% N.A.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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pavement preservation, the texture requirements cover three design parameters such as depth, groove, and land area. The texture for hard aggregate is 1.5 mm deep with 2.5e4.0 mm wide grooves and 2.0 mm wide lane area. In general, the texture depth does not vary from project to project. The land area, however, should be adjusted in terms of the hardness of aggregate. A larger land area is commonly utilized in pavements with softer aggregate. The texture depth required by FHWA is much less than that required by IGGA and is currently in general agreement with the texture depth requirements used by state DOTs (Caltrans, 2007; IowaDOT, 2009; ODOT, 2013). Fig. 1 presents two photos showing close-up views of the diamond-ground asphalt pavement on SR-162 and the diamond-ground concrete pavements on US-24, respectively.
2.2.
Field tests
Two types of field testing, laser scanner test and locked wheel test, were conducted to evaluate the surface frictional properties of the diamond-ground pavements. The laser scanner test was conducted to measure the surface texture of diamond-ground pavements. After an extensive comparison (Li et al., 2010), a 1kHz laser scanner was chosen to measure the texture for three reasons. First, the 1-kHz laser scanner is capable of measuring texture with wavelength as low as 0.03 mm. This allowed the authors not only to examine the macrotexture aspect, but also to roughly evaluate the microtexture aspect of those diamondground pavements. Microtexture is of significance for longterm pavement friction performance, particularly in the land area on diamond-ground pavements. Second, the software package allows users to evaluate both depth and asperity of the measured texture profile. The texture profile depth is measured in terms of the mean profile depth (MPD). The texture profile asperity is measured with either the slope variance (SV) or root mean square (RMS). The former indicates the sharpness of profile asperity and the latter indicates the magnitude of profile asperity. Third, the laser scanner is capable of producing up to 1200 scan lines in an area of 100 75 mm. This allows users to produce repeatable texture parameters and to capture the detailed surface features. The locked wheel test was conducted to measure the wet pavement skid resistance in accordance with ASTM E-274 using the standard smooth tire (ASTM International, 2008, 2011). There were two main reasons for the authors to conduct the locked wheel test. First, while traffic control was set-up for
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the laser scanner test, safety concerns did arise during testing due to heavy traffic and high vehicle speed. It appeared more realistic to conduct the locked wheel test, instead of the laser scanner test, on the interstate pavement and bridge deck. Second, while it is well known that pavement friction is dominated by both surface macrotexture and microtexture, no reported models can explicitly quantify the correlation between surface texture and friction. Henry reported that the smooth tire is more reliable to produce friction numbers which the ribbed tire (Henry, 2000). The horizontal and vertical forces at the tire-pavement interface are averaged to compute the friction or skid number which is the friction coefficient times 100 over a time interval of 1.0 s for the locked wheel tester used by the authors. Calibrations were conducted before field testing on water spray, speed, and skid resistance force to ensure test accuracy and reliability.
3.
Surface and texture profile features
3.1.
Surface profiles
In the analysis of macrotexture profiles, the measured profile was filtered to generate the macrotexture profile using a high pass of 50 mm and a low pass of 0.5 mm, i.e., the cutoff wavelengths for macrotexture. The data sample spacing was set to one third of the low pass, i.e., 0.167 mm. In the analysis of microtexture, however, the total profile was filtered to generate the microtexture profile using a high pass of 0.5 mm and a low pass of 0.03 mm, instead of the cutoff wavelengths for microtexture, and the data sample spacing was set to 0.01 mm accordingly. This is because the laser scanner used by the authors was only capable of measuring pavement texture in the wavelength range of 0.03 mme50 mm. As demonstrated in Fig. 2, the 3D surface profile plots generated using the macrotexture profiles and microtexture profiles on the diamond-ground asphalt and concrete pavements, respectively. The X-distance represents the transverse position, the Y-distance represents the longitudinal position, and the elevation represents the deviation of the diamondground surface from the mean profile surface. Apparently, the 3D surface profile plots can clearly show the positions of peaks and valleys, and also show the periodic distributions of land areas and grooves, particularly on the diamondground concrete pavement.
Fig. 1 e Close-ups of typical diamond-ground surfaces. (a) One-year old HMA. (b) New PCC. Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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For the surface macrotexture profiles, the valleys vary more significantly than the peaks, and the valley depths are greater than the peak heights on the diamond-ground asphalt pavement. On the diamond-ground concrete pavement, the valley depths may vary more or less significantly than the peak heights. However, the valley depths are slightly greater than the peak heights. For the microtexture profiles, the variation in valley depths is close to that in peak heights on the diamondground asphalt pavement and both the valley depths and peak heights are close to each other. Similar observations were also made on the diamond-ground concrete pavement. Overall, the longitudinal diamond-ground concrete pavements have more significant periodic trends than the longitudinal diamondground asphalt pavements. The longitudinal diamond-ground asphalt pavements have greater deviations than the diamondground concrete pavements. The valley depths and peak heights on the longitudinal diamond-ground asphalt pavements are both greater than the valley depths and peak heights on the diamond-ground concrete pavements.
3.2.
Texture profile parameters
Presented in Table 2 are the measured texture parameters MPD and RMS for both macrotexture and microtexture profiles on the ground pavements of SR-162 and US-24, respectively. In addition, the MPD and RMS measured in the transversely tined friction track are also presented in Table 2 for comparison. The diamond-ground asphalt pavement of SR-162 has been in service for five years. The diamondground concrete pavement has not been open to traffic at the time of texture testing. It is shown that the MPD and
RMS produced by longitudinal diamond grinding are much less than those by transverse tining. For the macrotexture produced by diamond grinding, the MPD and RMS have the same order of magnitude regardless of pavement type. Notice that the MPD and RMS on the diamond-ground asphalt pavements are in general greater than those on the diamond-ground concrete pavements while the former had a 5-year service life and the latter had a 0-year service life. One possible reason is that after the diamond-ground asphalt pavements was opened to traffic, the break-off of standing fins might occur due to the repeated application of vehicle tire, which could cause distortion on the surface. In addition, voids on the asphalt pavement surface could also contribute to increase macrotexture change. In general, it appears that diamond grinding can provide long-term macrotexture change for asphalt pavements. For the microtexture produced by diamond grinding, two observations can be found from the MPD and RMS values in Table 2. First, the RMS value is one order of magnitude greater than the corresponding MPD value, regardless of the type of pavement and grinding age. The authors also noticed that microtexture profiles with large MPD values usually tend to have larger RMS values. It is reported that the cutoff peak-topeak amplitudes are 0.001 mme0.5 mm (PIARC, 1987). Therefore, the microtexture MPD values are very small and basically fall in the lower range of microtexture cutoff depths. Moreover, the macrotexture MPD values are two orders of magnitude greater than the microtexture MPD values. The above observation implies that it may be more appropriate to use RMS, rather than MPD, to model microtexture effect on friction. Second, the microtexture MPD and RMS on the
Fig. 2 e 3D surface profile plots of longitudinal diamond-ground pavements. (a) HMA macrotexture (SR-162). (b) PCC macrotexture (US-24). (c) HMA microtexture (SR-162). (d) PCC microtexture (US-24). Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Table 2 e Texture parameters of longitudinal diamond-ground pavements. Road
Pavement type
SR-162 US-24 Friction track
Grinding age
Asphalt Concrete Concrete
60 months Zero N.A.
diamond-ground asphalt pavement are greater than those on the diamond-ground concrete pavement. Pavement surface microtexture relies mainly on the coarse aggregate. In reality, there is no much difference between the aggregate size used for concrete and asphalt pavement mixes (INDOT, 2014). However, there are slight differences in the physical quality requirements. HMA pavements generally require better angularity and LA abrasion.
Macrotexture
Microtexture
MPD (mm)
RMS (mm)
MPD (mm)
RMS (mm)
0.482e0.944 0.337e0.529 1.660
0.397e0.651 0.175e0.262 1.329
0.002e0.006 0.001e0.002 0.006
0.031e0.090 0.016e0.022 0.130
4.
Surface friction performance
grinding, however, provided numerous randomly spaced, shallow, and narrow grooves. Similar observations can be made for the microtexture profiles within a sampling length of 5 mm. So far, therefore, two implications can be drawn from the above analysis. First, pavement friction depends not only on texture depth and shape, but also on texture spacing and periodicity, and cannot be readily defined by a single texture profile parameter such as MPD. Second, the initial surface friction produced by longitudinal diamond grinding is equal to and even better than that produced by the conventional transverse tining.
4.1.
Initial friction level
4.2.
It is well known that the friction performance of diamondground pavement varies with many factors such as pavement type, aggregate type, and operation type. For the initial friction level, the operation type, i.e., preservation treatment for existing pavement or pavement re-profiling for new pavement, may play a critical role. As mentioned earlier, diamond grinding for pavement preservation generally aims at restoring surface friction on the existing pavement. Diamond grinding for pavement re-profiling, however, aims at improving surface smoothness on new pavements. Presented in Fig. 3 are the initial friction number (FN) measurements made on the two diamond-ground surfaces, including the bridge deck on I-80 and the new concrete pavement on US24, respectively. The former was to restore surface friction and the latter was to improve surface smoothness. To gain a better understanding of the initial friction level of longitudinal diamond grinding, Fig. 3 also provides the FN measured in the transversely tined friction track. The greatest FN is 63 occurred on the diamond-ground surface of US-24, and the smallest FN is around 47 in the diamondground bridge deck of I-80. In-between is 55 occurred on the transversely tined concrete surface. Notice that both the macrotexture and microtexture MPD and RMS values on the tined concrete (friction track in Table 2) are much greater than those on the longitudinally diamondground concrete pavement (US-24 in Table 2). However, the friction number on the longitudinally diamond-ground concrete pavement is eight digits greater than that in the transversely tined concrete track. In reality, pavement friction is the result of the combined effect of hysteresis and adhesion produced during the tire-pavement interaction at the interface and can become very complicated under real world conditions. As Fig. 4 and Fig. 5 show the typical macro and microtexture profiles on the transversely tined and longitudinally ground concrete surfaces, respectively. For the macrotexture profiles, the transverse tining provided five evenly spaced, 3 mme5 mm deep and 3 mm wide grooves within a sampling length of 100 mm. The longitudinal
Friction variations over time
Presented in Fig. 6 are the friction numbers measured over time on three diamond-ground pavements, including the diamondground asphalt pavement of SR-162, and the two diamondground concrete pavements of US-24 and US-50, respectively (Table 1). Three observations can be made through careful inspection of the curves in Fig. 6. First, the friction number is around 63 on the diamond-ground new concrete pavement of US-24 before opening to traffic, and decreases by 11% after nine months of service. The friction number is 41 on the diamond-ground concrete pavement of US-50 after 4 months of service and 36 on the diamond-ground asphalt pavement of SR-162 after two months of service. While the authors were unable to measure the friction numbers on both US-50 and SR162 before opening to traffic, the above observation may be extended to imply that the surface friction on diamondground pavements may experience great decrease after opening to traffic. On a newly diamond-ground surface, thin fins standing in the ground surface commonly produce great surface friction. However, those thin fins can be knocked off quickly by vehicle tires, particularly truck tires after opening to traffic. Consequently, the ground surface may become more uniform, which therefore leads to a reduction in surface friction.
Fig. 3 e Initial friction levels on ground and tined concrete pavements.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Fig. 4 e Surface macrotexture profiles from INDOT friction track. (a) Transverse tining. (b) Longitudinal grinding.
Fig. 5 e Surface microtexture profiles from INDOT friction track. (a) Transverse tining. (b) Longitudinal grinding.
Second, the surface friction numbers on the diamondground concrete pavements of both US-24 and US-50 experienced an ever-decreasing trend with service life. The friction number on the diamond-ground asphalt pavement of SR-162, however, fluctuated over time, particularly after 24 months of service. The friction numbers on the ground asphalt pavement of SR-162 were initially less than and then, became greater than those on both US-24 and US-50 after 24 months of services. The underlying reason may be that the asphalt surface deteriorates due to aging and raveling with time. This confirms the two earlier statements, i.e., the diamond-ground asphalt pavements have greater deviations than the diamond-ground concrete pavements and the texture MPD and RMS on the diamond-ground asphalt pavements are in general greater than those on the diamond-ground concrete pavements. The third observation is that while the diamondground concrete pavements demonstrated an ever-decreasing trend, the friction number on US-50 is around 25 measured using the standard smooth at 40 mph after 64 months of service. While the friction number decreased by more than 35% compared to that measured five years ago, the longitudinal diamond grinding on US-50 did provide durable friction performance taking into consideration the high traffic volume and the presence of signalized intersections.
5.
Conclusions
This paper presents a field evaluation of the surface texture and friction characteristics on longitudinally diamond-ground concrete and asphalt pavements in terms of surface macrotexture
and microtexture and locked wheel friction number. Based on the field test and observations, four main conclusions can be drawn as follows: The longitudinal diamond-ground asphalt pavements may have greater surface deviations than the diamond-ground concrete pavements. The valley depths and peak heights on the longitudinal diamond-ground asphalt pavements are also greater than the valley depths and peak heights on the diamond-ground concrete pavements, respectively. For macrotexture profiles on diamond-ground pavements, MPD and RMS have the same order of magnitude regardless of pavement type. However, MPD and RMS produced by longitudinal diamond grinding are much less than those by transverse tining. The MPD and RMS on the diamond-ground asphalt pavements are greater than those on the diamondground concrete pavements. For microtexture profiles on diamond-ground pavements, the RMS is one order of magnitude greater than the corresponding MPD, regardless of the type of pavement. The MPD and RMS on the diamond-ground asphalt pavement are greater than those on the diamondground concrete pavement. In general, the microtexture MPD values are very small and fall in the lower range of microtexture cutoff depths. Therefore, it may be more appropriate to use RMS, rather than MPD, in modeling the effect of microtexture on friction. Generally, conventional transverse tining can produce greater texture than longitudinal grinding. However, the surface friction produced by longitudinal diamond grinding may be equal to and even better than that produced by conventional transverse tining. Pavement friction depends not only on texture depth and shape, but also on texture spacing and periodicity. For
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Fig. 6 e Diamond-ground pavement friction variations over time.
diamond-ground pavements, surface friction cannot be readily defined by a single texture profile parameter such as MPD. Surface friction on diamond-ground pavements may experience great decrease after opening to traffic. The surface friction on diamond-ground concrete pavements tends to have an ever-decreasing trend. The surface friction on diamond-ground asphalt pavements, however, tends to fluctuate with service life. Overall, diamond grinding can provide durable, satisfactory surface friction performance for both concrete and asphalt pavements.
Acknowledgments The authors would like to thank Mike Prather, Craig Allman, and David Dallas of INDOT for their assistance in selecting test sections. The supports from Steve Dick, Harry Greer, and Patrick Weaver of INDOT in field testing are also acknowledged. The contents of this paper reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of INDOT. This paper does not constitute a standard, specification, or regulation.
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Caltrans, 2007. Maintenance Technical Advisory Guide (MTAG) Volume II-rigid Pavement Preservation, second ed. Caltrans, Sacramento. FHWA, 2005. Pavement Preservation Checklist Series, No. 7, Diamond Grinding of Portland Cement Concrete Pavement. FHWA-IF-03e040. FHWA, Washington DC. Gallaway, B.M., Ivey Jr., D.L., Ross, H.E., et al., 1979. Tentative Pavement and Geometric Design Criteria for Minimizing Hydroplaning. FHWA-RD-79e31. FHWA, Washington DC. Henry, J., 2000. Evaluation of Pavement Friction Characteristics. NCHRP Synthesis 291. TRB, Washington DC. IGGA, 2014a. IGGA Guide Specification: Conventional Diamond Grinding of City Streets. IGGA, West Coxsackie. IGGA, 2014b. IGGA Guide Specification: Diamond Grinding Asphalt Pavements. IGGA, West Coxsackie. IGGA, 2014c. IGGA Guide Specification: Conventional Diamond Grinding for Pavement Preservation. IGGA, West Coxsackie. INDOT, 2014. Standard Specifications. INDOT, Indianapolis. IowaDOT, 2009. Standard Specifications for Highway and Bridge Construction. Iowa Department of Transportation, Ames. ISP, 2012. Automated Reporting Information Exchange System (ARIES). Indiana State Police, Indianapolis. Kummer, H.W., Meyer, W.E., 1967. Tentative Skid Resistance Requirements for Main Rural Highways. NCHRP-37. Highway Research Board, National Research Council, Washington DC. Li, S., Noureldin, S., Zhu, K., 2010. Safety Enhancement of the INDOT Network Pavement Friction Testing Program: Macrotexture and Microtexture Testing Using Laser Sensors. FHWA/IN/JTRP-2010/25. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette. NDOR, 2002. Pavement Maintenance Manual. Nebraska Department of Roads, Lincoln. Nelson, M., Miller, J.P., Zisman, I., et al., 2011. Best Practice in Lane Departure Avoidance and Traffic Calming. NCHRP Project 20e68A, Scan 09-03. TRB, Washington DC. ODOT, 2013. Construction and Material Specifications. Ohio Department of Transportation, Columbus. Ong, G.P., Fwa, T.F., Guo, J., 2005. Modeling hydroplaning and effects of pavement microtexture. Transportation Research Record 1905, 166e176. PIARC, 1987. Optimization of pavement surface characteristics, PIARC technical committee on surface characteristics. In: 18th World Road Congress, Brussels, 1987. Rao, S., Yu, H.T., Khazanovich, L., et al., 1999. Longevity of diamond-ground concrete pavements. In: 78th TRB Annual Meeting, Washington DC, 1999. TRB, 1972. Frictional and Retarding Forces on Aircraft Tyres, Part I: Introduction. ESDU-71025-PT-1. TRB, Washington DC.
references
ACPA, 2006. Diamond Grinding Shines in California and Missouri. R&T Update. Concrete Pavement Research & Technology, Boston. ASTM International, 2008. Standard Specification for Standard Smooth Tire for Pavement Skid-resistance Tests. ASTM E524e08. ASTM, West Conshohocken. ASTM International, 2011. Standard Test Method for Skid Resistance of Paved Surfaces Using a Full-scale Tire. ASTM E274/E274M-11. ASTM, West Conshohocken. Browne, A.L., 1975. Mathematical Analysis for Pneumatic Tire Hydroplaning. ASTM STP 583. ASTM, West Conshohocken. Caltrans, 2005. The Effectiveness of Diamond Grinding Concrete Pavements in California. Caltrans, Sacramento.
Shuo Li received a BEng in Highway and Urban Street Engineering from Tongji University, an MEng in Highway Engineering from Xian Highway Institute, and a PhD in Transportation Engineering from National University of Singapore. Dr. Li also conducted his postdoctoral studies at School of Civil Engineering, Purdue University. Dr. Li is currently a licensed professional civil engineer in Indiana and working with Division of Research and Development, Indiana Department of Transportation. His research interests lie primarily in the area of highway transportation. His research focuses on understanding tire-pavement interaction and traffic safety.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Dwayne Harris received a BS in Geophysical Engineering and an MS in Mining Engineering from Montana Tech, and a PhD from School of Civil Engineering at Purdue University. Dr. Harris is a licensed professional engineer and professional geologist in the state of Indiana. Dr. Harris has been employed with the office of research and development of INDOT since 2002. Where his work is primarily focused on research and specialized testing including ground penetrating radar (GPR) and inertial profiling (pavement smoothness). Prior to joining Indiana Department of Transportation his background includes work in the mining industry, and work as a GPR consultant.
Tim Wells received both his BS and MS degrees in Transportation Engineering from School of Civil Engineering at Purdue University. Mr. Wells is a licensed professional engineer in civil engineering in the state of Indiana. He had many years of county engineering experience before joining Indiana Department of Transportation. Mr. Wells is now Section Manager in the Division of Research and Development, Indiana Department of Transportation. His research interests include intelligent transportation system (ITS) and traffic control devices. Recently, Mr. Wells moved his research interest into non-destructive bridge testing.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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ScienceDirect journal homepage: www.elsevier.com/locate/jtte
Original Research Paper
Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements Q1
Shuo Li*, Dwayne Harris, Tim Wells Division of Research and Development, Indiana Department of Transportation, West Lafayette, IN 47906, USA
article info
abstract
Article history:
Recently, diamond grinding has gained increasing attention as pavement preservation
Available online xxx
treatment to restore desired surface characteristics, particularly friction. Compared to other pavement preservation treatments such as surface overlays and high friction surface treatments, diamond grinding may cost less, save construction time, or require minimum
Keywords:
maintenance. Diamond grinding produces longitudinal, continuous, and line-type texture
Concrete pavement
that contains corrugations with evenly spaced ridges. The improved surface texture will
Asphalt pavement
immediately enhance pavement surface friction and reduce the possibility of hydroplaning
Surface friction
in rainy weather. However, little information has been documented on the texture charac-
Diamond-grinding
teristics and long-term friction performance of diamond-ground pavements. A field evalu-
Macrotexture
ation was conducted to examine the surface texture and friction characteristics in diamond-
Microtexture
ground concrete and asphalt pavements by the authors. Five pavement test sections, including two diamond-ground concrete pavements, one diamond-ground concrete bridge deck, one diamond-ground asphalt pavement, and one transversely tined concrete pavement, were selected for evaluation. Laser scanner testing was performed to capture both macro and microtexture profiles. Locked wheel testing was performed to measure the friction numbers. The test results were examined and compared so as to evaluate two performances, after construction and long-term friction performance of diamond-ground pavements. It was found that longitudinal diamond grinding can provide durable, satisfactory surface friction performance for both concrete and asphalt pavements. © 2016 Periodical Offices of Chang'an University. Production and hosting by Elsevier B.V. on behalf of Owner. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1.
Introduction
Diamond grinding is a widely accepted practice to remove bumps and rectify surface defects on concrete pavements. It has been effectively used as part of concrete pavement restoration (CPR) since 1965 (ACPA, 2006; Caltrans, 2005). A
study surveyed a total of 76 diamond-ground concrete pavements from 9 states and found that the average life of a typical diamond-ground concrete pavement was about 14 years (Rao et al., 1999). It was also found that after diamond grinding, the pavement surface texture increased, and skid resistance improved considerably and the ground surfaces could last for 8e15 years. Although diamond grinding has been mainly
* Corresponding author. Tel.: þ1 765 463 1521, Fax: þ1 765 497 1665. E-mail addresses: [email protected] (S. Li), [email protected] (D. Harris), [email protected] (T. Wells). Peer review under responsibility of Periodical Offices of Chang'an University. http://dx.doi.org/10.1016/j.jtte.2016.08.001 2095-7564/© 2016 Periodical Offices of Chang'an University. Production and hosting by Elsevier B.V. on behalf of Owner. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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J. Traffic Transp. Eng. (Engl. Ed.) 2016; x (x): 1e8
used to correct pavement profile, it has also found other methods, such as restoring pavement cross-sections with rutting greater than 13 mm (NDOR, 2002). To date, the identified advantages of diamond grinding include better ride quality, enhanced safety, quieter travel surface, extended service life, and reduced rehabilitation costs. Compared to other pavement preservation treatments such as overlays and high friction surface treatments, diamond grinding may cost less, save construction time, and produce minimum traffic interruption during construction. Diamond grinding also allows treating local problems and small areas. In addition, diamond grinding always produces an immediate increase in surface friction regardless of the effect of existing pavement and grinding operation. Consequently, diamond grinding has gained increasing attention as pavement preservation treatment to restore desired surface characteristics such as ride, noise, friction, and drainage on existing pavements. The International Grooving and Grinding Association (IGGA) has developed guide specifications for use of diamond grinding in three different operations, city streets, asphalt pavements, and pavement preservation (IGGA, 2014a, 2014b, 2014c). Federal Highway Administration (FHWA) has also provided requirements for diamond grinding for concrete pavement preservation (FHWA, 2005). Although diamond grindings in different operations may have a different purpose, i.e., to provide desired surface characteristics or to eliminate surface defects, diamond grindings in most operations follow similar procedures so as to provide longitudinal and continuous diamond grinding on pavements. In short, diamond grinding will inevitably restore surface friction characteristics through providing line-type texture that contains corrugations with evenly spaced ridges. The immediate result is the improved surface texture that will ultimately enhance pavement surface friction and reduce the possibility of hydroplaning in rainy weather. However, little information has been documented on the texture characteristics and long-term friction performance of diamond-ground pavements. Wet pavement friction is dominated by both surface macrotexture and microtexture (Kummer and Meyer, 1967; PIARC, 1987). Macrotexture provides channels for removal of water and reduces dynamic hydroplaning development (Gallaway et al., 1979; TRB, 1972). Microtexture punctures and drains the viscous water film between tire and pavement reducing the viscous hydroplaning development. Good microtexture reduces the likelihood of hydroplaning development (Browne, 1975; Ong et al., 2005). Also, microtexture may play an important role in reduction of dry pavement skidding accident. In reality, lanedeparture crashes account for 53% of all roadway fatalities (Nelson et al., 2011). The Indiana crash data also suggests that
during summer time, up to 88% of lane-departure crashes occur on dry pavements (ISP, 2012). Recently, diamond grinding has been used in Indiana on different pavements, including concrete pavements, asphalt pavements, and bridge decks. This paper documents the texture and friction test data and analysis results on these diamond-ground pavements. Such information will be useful to pavement engineers in better understanding the long-term friction performance and the proper use of diamond grinding in pavement and bridge deck preservations.
2.
Test sections and field tests
2.1.
Test sections
In order to examine the texture and friction characteristics of longitudinally diamond-ground hot mix asphalt (HMA) and Portland cement concrete (PCC) pavements, a total of five pavement test sections, four diamond-ground test sections and one transversely tined test section, as shown in Table 1, were selected for field testing and evaluation. The selection of these five test sections was based on pavement type, purpose of grinding, and performance comparison. The test section on SR-162 was classified as minor arterial and diamond grinding was used to re-profile the surface of new asphalt pavement. The test section on US-24 consisted of two lanes in each direction, and was classified as rural expressway. The pavement was newly constructed concrete pavement. Diamond grinding was completed to remove localized bumps before opening to traffic. The test section on US-50, consisting of two lanes in each direction, was classified as principal arterial in urban area. This section has several signalized intersections and the purpose of diamond grinding was to improve surface smoothness and friction of the new concrete pavement, particularly on intersection approaches. The diamond-ground bridge deck is located on I-80 in the north of Indiana and diamond grinding was used solely to restore polished deck surface. All of the above four test sections have high traffic volumes. In particular, the section on US-50 and the bridge deck on I-80 have heavy truck traffic. The friction track is part of the test track constructed by the Indiana Department of Transportation (INDOT) for validating friction test system and is not to the public. Although IGGA has developed specifications for conventional diamond grinding of city streets, diamond grinding asphalts, and diamond grinding for pavement preservation, respectively. These three specifications are aimed at providing the same final surface finish, i.e., longitudinal, corduroy-type texture with ridge peaks approximately 1.5e4.8 mm above the grooves. In the FHWA diamond grinding checklist for concrete
Table 1 e General information on selected pavement test sections. Road SR-162 US-24 US-50 I-80 Friction track
Classification
Pavement type
Grinding year
AADT
Truck traffic
Minor arterial Rural expressway Principal arterial Interstate N.A.
HMA PCC PCC PCC deck Tined PCC
2008 2012 2008 2013 N.A.
5095 8757 33,143 25,932 N.A.
9.6% 36.6% 5.7% 24.4% N.A.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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pavement preservation, the texture requirements cover three design parameters such as depth, groove, and land area. The texture for hard aggregate is 1.5 mm deep with 2.5e4.0 mm wide grooves and 2.0 mm wide lane area. In general, the texture depth does not vary from project to project. The land area, however, should be adjusted in terms of the hardness of aggregate. A larger land area is commonly utilized in pavements with softer aggregate. The texture depth required by FHWA is much less than that required by IGGA and is currently in general agreement with the texture depth requirements used by state DOTs (Caltrans, 2007; IowaDOT, 2009; ODOT, 2013). Fig. 1 presents two photos showing close-up views of the diamond-ground asphalt pavement on SR-162 and the diamond-ground concrete pavements on US-24, respectively.
2.2.
Field tests
Two types of field testing, laser scanner test and locked wheel test, were conducted to evaluate the surface frictional properties of the diamond-ground pavements. The laser scanner test was conducted to measure the surface texture of diamond-ground pavements. After an extensive comparison (Li et al., 2010), a 1kHz laser scanner was chosen to measure the texture for three reasons. First, the 1-kHz laser scanner is capable of measuring texture with wavelength as low as 0.03 mm. This allowed the authors not only to examine the macrotexture aspect, but also to roughly evaluate the microtexture aspect of those diamondground pavements. Microtexture is of significance for longterm pavement friction performance, particularly in the land area on diamond-ground pavements. Second, the software package allows users to evaluate both depth and asperity of the measured texture profile. The texture profile depth is measured in terms of the mean profile depth (MPD). The texture profile asperity is measured with either the slope variance (SV) or root mean square (RMS). The former indicates the sharpness of profile asperity and the latter indicates the magnitude of profile asperity. Third, the laser scanner is capable of producing up to 1200 scan lines in an area of 100 75 mm. This allows users to produce repeatable texture parameters and to capture the detailed surface features. The locked wheel test was conducted to measure the wet pavement skid resistance in accordance with ASTM E-274 using the standard smooth tire (ASTM International, 2008, 2011). There were two main reasons for the authors to conduct the locked wheel test. First, while traffic control was set-up for
3
the laser scanner test, safety concerns did arise during testing due to heavy traffic and high vehicle speed. It appeared more realistic to conduct the locked wheel test, instead of the laser scanner test, on the interstate pavement and bridge deck. Second, while it is well known that pavement friction is dominated by both surface macrotexture and microtexture, no reported models can explicitly quantify the correlation between surface texture and friction. Henry reported that the smooth tire is more reliable to produce friction numbers which the ribbed tire (Henry, 2000). The horizontal and vertical forces at the tire-pavement interface are averaged to compute the friction or skid number which is the friction coefficient times 100 over a time interval of 1.0 s for the locked wheel tester used by the authors. Calibrations were conducted before field testing on water spray, speed, and skid resistance force to ensure test accuracy and reliability.
3.
Surface and texture profile features
3.1.
Surface profiles
In the analysis of macrotexture profiles, the measured profile was filtered to generate the macrotexture profile using a high pass of 50 mm and a low pass of 0.5 mm, i.e., the cutoff wavelengths for macrotexture. The data sample spacing was set to one third of the low pass, i.e., 0.167 mm. In the analysis of microtexture, however, the total profile was filtered to generate the microtexture profile using a high pass of 0.5 mm and a low pass of 0.03 mm, instead of the cutoff wavelengths for microtexture, and the data sample spacing was set to 0.01 mm accordingly. This is because the laser scanner used by the authors was only capable of measuring pavement texture in the wavelength range of 0.03 mme50 mm. As demonstrated in Fig. 2, the 3D surface profile plots generated using the macrotexture profiles and microtexture profiles on the diamond-ground asphalt and concrete pavements, respectively. The X-distance represents the transverse position, the Y-distance represents the longitudinal position, and the elevation represents the deviation of the diamondground surface from the mean profile surface. Apparently, the 3D surface profile plots can clearly show the positions of peaks and valleys, and also show the periodic distributions of land areas and grooves, particularly on the diamondground concrete pavement.
Fig. 1 e Close-ups of typical diamond-ground surfaces. (a) One-year old HMA. (b) New PCC. Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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For the surface macrotexture profiles, the valleys vary more significantly than the peaks, and the valley depths are greater than the peak heights on the diamond-ground asphalt pavement. On the diamond-ground concrete pavement, the valley depths may vary more or less significantly than the peak heights. However, the valley depths are slightly greater than the peak heights. For the microtexture profiles, the variation in valley depths is close to that in peak heights on the diamondground asphalt pavement and both the valley depths and peak heights are close to each other. Similar observations were also made on the diamond-ground concrete pavement. Overall, the longitudinal diamond-ground concrete pavements have more significant periodic trends than the longitudinal diamondground asphalt pavements. The longitudinal diamond-ground asphalt pavements have greater deviations than the diamondground concrete pavements. The valley depths and peak heights on the longitudinal diamond-ground asphalt pavements are both greater than the valley depths and peak heights on the diamond-ground concrete pavements.
3.2.
Texture profile parameters
Presented in Table 2 are the measured texture parameters MPD and RMS for both macrotexture and microtexture profiles on the ground pavements of SR-162 and US-24, respectively. In addition, the MPD and RMS measured in the transversely tined friction track are also presented in Table 2 for comparison. The diamond-ground asphalt pavement of SR-162 has been in service for five years. The diamondground concrete pavement has not been open to traffic at the time of texture testing. It is shown that the MPD and
RMS produced by longitudinal diamond grinding are much less than those by transverse tining. For the macrotexture produced by diamond grinding, the MPD and RMS have the same order of magnitude regardless of pavement type. Notice that the MPD and RMS on the diamond-ground asphalt pavements are in general greater than those on the diamond-ground concrete pavements while the former had a 5-year service life and the latter had a 0-year service life. One possible reason is that after the diamond-ground asphalt pavements was opened to traffic, the break-off of standing fins might occur due to the repeated application of vehicle tire, which could cause distortion on the surface. In addition, voids on the asphalt pavement surface could also contribute to increase macrotexture change. In general, it appears that diamond grinding can provide long-term macrotexture change for asphalt pavements. For the microtexture produced by diamond grinding, two observations can be found from the MPD and RMS values in Table 2. First, the RMS value is one order of magnitude greater than the corresponding MPD value, regardless of the type of pavement and grinding age. The authors also noticed that microtexture profiles with large MPD values usually tend to have larger RMS values. It is reported that the cutoff peak-topeak amplitudes are 0.001 mme0.5 mm (PIARC, 1987). Therefore, the microtexture MPD values are very small and basically fall in the lower range of microtexture cutoff depths. Moreover, the macrotexture MPD values are two orders of magnitude greater than the microtexture MPD values. The above observation implies that it may be more appropriate to use RMS, rather than MPD, to model microtexture effect on friction. Second, the microtexture MPD and RMS on the
Fig. 2 e 3D surface profile plots of longitudinal diamond-ground pavements. (a) HMA macrotexture (SR-162). (b) PCC macrotexture (US-24). (c) HMA microtexture (SR-162). (d) PCC microtexture (US-24). Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Table 2 e Texture parameters of longitudinal diamond-ground pavements. Road
Pavement type
SR-162 US-24 Friction track
Grinding age
Asphalt Concrete Concrete
60 months Zero N.A.
diamond-ground asphalt pavement are greater than those on the diamond-ground concrete pavement. Pavement surface microtexture relies mainly on the coarse aggregate. In reality, there is no much difference between the aggregate size used for concrete and asphalt pavement mixes (INDOT, 2014). However, there are slight differences in the physical quality requirements. HMA pavements generally require better angularity and LA abrasion.
Macrotexture
Microtexture
MPD (mm)
RMS (mm)
MPD (mm)
RMS (mm)
0.482e0.944 0.337e0.529 1.660
0.397e0.651 0.175e0.262 1.329
0.002e0.006 0.001e0.002 0.006
0.031e0.090 0.016e0.022 0.130
4.
Surface friction performance
grinding, however, provided numerous randomly spaced, shallow, and narrow grooves. Similar observations can be made for the microtexture profiles within a sampling length of 5 mm. So far, therefore, two implications can be drawn from the above analysis. First, pavement friction depends not only on texture depth and shape, but also on texture spacing and periodicity, and cannot be readily defined by a single texture profile parameter such as MPD. Second, the initial surface friction produced by longitudinal diamond grinding is equal to and even better than that produced by the conventional transverse tining.
4.1.
Initial friction level
4.2.
It is well known that the friction performance of diamondground pavement varies with many factors such as pavement type, aggregate type, and operation type. For the initial friction level, the operation type, i.e., preservation treatment for existing pavement or pavement re-profiling for new pavement, may play a critical role. As mentioned earlier, diamond grinding for pavement preservation generally aims at restoring surface friction on the existing pavement. Diamond grinding for pavement re-profiling, however, aims at improving surface smoothness on new pavements. Presented in Fig. 3 are the initial friction number (FN) measurements made on the two diamond-ground surfaces, including the bridge deck on I-80 and the new concrete pavement on US24, respectively. The former was to restore surface friction and the latter was to improve surface smoothness. To gain a better understanding of the initial friction level of longitudinal diamond grinding, Fig. 3 also provides the FN measured in the transversely tined friction track. The greatest FN is 63 occurred on the diamond-ground surface of US-24, and the smallest FN is around 47 in the diamondground bridge deck of I-80. In-between is 55 occurred on the transversely tined concrete surface. Notice that both the macrotexture and microtexture MPD and RMS values on the tined concrete (friction track in Table 2) are much greater than those on the longitudinally diamondground concrete pavement (US-24 in Table 2). However, the friction number on the longitudinally diamond-ground concrete pavement is eight digits greater than that in the transversely tined concrete track. In reality, pavement friction is the result of the combined effect of hysteresis and adhesion produced during the tire-pavement interaction at the interface and can become very complicated under real world conditions. As Fig. 4 and Fig. 5 show the typical macro and microtexture profiles on the transversely tined and longitudinally ground concrete surfaces, respectively. For the macrotexture profiles, the transverse tining provided five evenly spaced, 3 mme5 mm deep and 3 mm wide grooves within a sampling length of 100 mm. The longitudinal
Friction variations over time
Presented in Fig. 6 are the friction numbers measured over time on three diamond-ground pavements, including the diamondground asphalt pavement of SR-162, and the two diamondground concrete pavements of US-24 and US-50, respectively (Table 1). Three observations can be made through careful inspection of the curves in Fig. 6. First, the friction number is around 63 on the diamond-ground new concrete pavement of US-24 before opening to traffic, and decreases by 11% after nine months of service. The friction number is 41 on the diamond-ground concrete pavement of US-50 after 4 months of service and 36 on the diamond-ground asphalt pavement of SR-162 after two months of service. While the authors were unable to measure the friction numbers on both US-50 and SR162 before opening to traffic, the above observation may be extended to imply that the surface friction on diamondground pavements may experience great decrease after opening to traffic. On a newly diamond-ground surface, thin fins standing in the ground surface commonly produce great surface friction. However, those thin fins can be knocked off quickly by vehicle tires, particularly truck tires after opening to traffic. Consequently, the ground surface may become more uniform, which therefore leads to a reduction in surface friction.
Fig. 3 e Initial friction levels on ground and tined concrete pavements.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Fig. 4 e Surface macrotexture profiles from INDOT friction track. (a) Transverse tining. (b) Longitudinal grinding.
Fig. 5 e Surface microtexture profiles from INDOT friction track. (a) Transverse tining. (b) Longitudinal grinding.
Second, the surface friction numbers on the diamondground concrete pavements of both US-24 and US-50 experienced an ever-decreasing trend with service life. The friction number on the diamond-ground asphalt pavement of SR-162, however, fluctuated over time, particularly after 24 months of service. The friction numbers on the ground asphalt pavement of SR-162 were initially less than and then, became greater than those on both US-24 and US-50 after 24 months of services. The underlying reason may be that the asphalt surface deteriorates due to aging and raveling with time. This confirms the two earlier statements, i.e., the diamond-ground asphalt pavements have greater deviations than the diamond-ground concrete pavements and the texture MPD and RMS on the diamond-ground asphalt pavements are in general greater than those on the diamond-ground concrete pavements. The third observation is that while the diamondground concrete pavements demonstrated an ever-decreasing trend, the friction number on US-50 is around 25 measured using the standard smooth at 40 mph after 64 months of service. While the friction number decreased by more than 35% compared to that measured five years ago, the longitudinal diamond grinding on US-50 did provide durable friction performance taking into consideration the high traffic volume and the presence of signalized intersections.
5.
Conclusions
This paper presents a field evaluation of the surface texture and friction characteristics on longitudinally diamond-ground concrete and asphalt pavements in terms of surface macrotexture
and microtexture and locked wheel friction number. Based on the field test and observations, four main conclusions can be drawn as follows: The longitudinal diamond-ground asphalt pavements may have greater surface deviations than the diamond-ground concrete pavements. The valley depths and peak heights on the longitudinal diamond-ground asphalt pavements are also greater than the valley depths and peak heights on the diamond-ground concrete pavements, respectively. For macrotexture profiles on diamond-ground pavements, MPD and RMS have the same order of magnitude regardless of pavement type. However, MPD and RMS produced by longitudinal diamond grinding are much less than those by transverse tining. The MPD and RMS on the diamond-ground asphalt pavements are greater than those on the diamondground concrete pavements. For microtexture profiles on diamond-ground pavements, the RMS is one order of magnitude greater than the corresponding MPD, regardless of the type of pavement. The MPD and RMS on the diamond-ground asphalt pavement are greater than those on the diamondground concrete pavement. In general, the microtexture MPD values are very small and fall in the lower range of microtexture cutoff depths. Therefore, it may be more appropriate to use RMS, rather than MPD, in modeling the effect of microtexture on friction. Generally, conventional transverse tining can produce greater texture than longitudinal grinding. However, the surface friction produced by longitudinal diamond grinding may be equal to and even better than that produced by conventional transverse tining. Pavement friction depends not only on texture depth and shape, but also on texture spacing and periodicity. For
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Fig. 6 e Diamond-ground pavement friction variations over time.
diamond-ground pavements, surface friction cannot be readily defined by a single texture profile parameter such as MPD. Surface friction on diamond-ground pavements may experience great decrease after opening to traffic. The surface friction on diamond-ground concrete pavements tends to have an ever-decreasing trend. The surface friction on diamond-ground asphalt pavements, however, tends to fluctuate with service life. Overall, diamond grinding can provide durable, satisfactory surface friction performance for both concrete and asphalt pavements.
Acknowledgments The authors would like to thank Mike Prather, Craig Allman, and David Dallas of INDOT for their assistance in selecting test sections. The supports from Steve Dick, Harry Greer, and Patrick Weaver of INDOT in field testing are also acknowledged. The contents of this paper reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of INDOT. This paper does not constitute a standard, specification, or regulation.
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Caltrans, 2007. Maintenance Technical Advisory Guide (MTAG) Volume II-rigid Pavement Preservation, second ed. Caltrans, Sacramento. FHWA, 2005. Pavement Preservation Checklist Series, No. 7, Diamond Grinding of Portland Cement Concrete Pavement. FHWA-IF-03e040. FHWA, Washington DC. Gallaway, B.M., Ivey Jr., D.L., Ross, H.E., et al., 1979. Tentative Pavement and Geometric Design Criteria for Minimizing Hydroplaning. FHWA-RD-79e31. FHWA, Washington DC. Henry, J., 2000. Evaluation of Pavement Friction Characteristics. NCHRP Synthesis 291. TRB, Washington DC. IGGA, 2014a. IGGA Guide Specification: Conventional Diamond Grinding of City Streets. IGGA, West Coxsackie. IGGA, 2014b. IGGA Guide Specification: Diamond Grinding Asphalt Pavements. IGGA, West Coxsackie. IGGA, 2014c. IGGA Guide Specification: Conventional Diamond Grinding for Pavement Preservation. IGGA, West Coxsackie. INDOT, 2014. Standard Specifications. INDOT, Indianapolis. IowaDOT, 2009. Standard Specifications for Highway and Bridge Construction. Iowa Department of Transportation, Ames. ISP, 2012. Automated Reporting Information Exchange System (ARIES). Indiana State Police, Indianapolis. Kummer, H.W., Meyer, W.E., 1967. Tentative Skid Resistance Requirements for Main Rural Highways. NCHRP-37. Highway Research Board, National Research Council, Washington DC. Li, S., Noureldin, S., Zhu, K., 2010. Safety Enhancement of the INDOT Network Pavement Friction Testing Program: Macrotexture and Microtexture Testing Using Laser Sensors. FHWA/IN/JTRP-2010/25. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette. NDOR, 2002. Pavement Maintenance Manual. Nebraska Department of Roads, Lincoln. Nelson, M., Miller, J.P., Zisman, I., et al., 2011. Best Practice in Lane Departure Avoidance and Traffic Calming. NCHRP Project 20e68A, Scan 09-03. TRB, Washington DC. ODOT, 2013. Construction and Material Specifications. Ohio Department of Transportation, Columbus. Ong, G.P., Fwa, T.F., Guo, J., 2005. Modeling hydroplaning and effects of pavement microtexture. Transportation Research Record 1905, 166e176. PIARC, 1987. Optimization of pavement surface characteristics, PIARC technical committee on surface characteristics. In: 18th World Road Congress, Brussels, 1987. Rao, S., Yu, H.T., Khazanovich, L., et al., 1999. Longevity of diamond-ground concrete pavements. In: 78th TRB Annual Meeting, Washington DC, 1999. TRB, 1972. Frictional and Retarding Forces on Aircraft Tyres, Part I: Introduction. ESDU-71025-PT-1. TRB, Washington DC.
references
ACPA, 2006. Diamond Grinding Shines in California and Missouri. R&T Update. Concrete Pavement Research & Technology, Boston. ASTM International, 2008. Standard Specification for Standard Smooth Tire for Pavement Skid-resistance Tests. ASTM E524e08. ASTM, West Conshohocken. ASTM International, 2011. Standard Test Method for Skid Resistance of Paved Surfaces Using a Full-scale Tire. ASTM E274/E274M-11. ASTM, West Conshohocken. Browne, A.L., 1975. Mathematical Analysis for Pneumatic Tire Hydroplaning. ASTM STP 583. ASTM, West Conshohocken. Caltrans, 2005. The Effectiveness of Diamond Grinding Concrete Pavements in California. Caltrans, Sacramento.
Shuo Li received a BEng in Highway and Urban Street Engineering from Tongji University, an MEng in Highway Engineering from Xian Highway Institute, and a PhD in Transportation Engineering from National University of Singapore. Dr. Li also conducted his postdoctoral studies at School of Civil Engineering, Purdue University. Dr. Li is currently a licensed professional civil engineer in Indiana and working with Division of Research and Development, Indiana Department of Transportation. His research interests lie primarily in the area of highway transportation. His research focuses on understanding tire-pavement interaction and traffic safety.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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Dwayne Harris received a BS in Geophysical Engineering and an MS in Mining Engineering from Montana Tech, and a PhD from School of Civil Engineering at Purdue University. Dr. Harris is a licensed professional engineer and professional geologist in the state of Indiana. Dr. Harris has been employed with the office of research and development of INDOT since 2002. Where his work is primarily focused on research and specialized testing including ground penetrating radar (GPR) and inertial profiling (pavement smoothness). Prior to joining Indiana Department of Transportation his background includes work in the mining industry, and work as a GPR consultant.
Tim Wells received both his BS and MS degrees in Transportation Engineering from School of Civil Engineering at Purdue University. Mr. Wells is a licensed professional engineer in civil engineering in the state of Indiana. He had many years of county engineering experience before joining Indiana Department of Transportation. Mr. Wells is now Section Manager in the Division of Research and Development, Indiana Department of Transportation. His research interests include intelligent transportation system (ITS) and traffic control devices. Recently, Mr. Wells moved his research interest into non-destructive bridge testing.
Please cite this article in press as: Li, S., et al., Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements, Journal of Traffic and Transportation Engineering (English Edition) (2016), http://dx.doi.org/10.1016/ j.jtte.2016.08.001
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