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ACI 325.6R-88(Reapproved 1997)

Texturing Concrete Pavements

Reported by ACI Committee 325

Ralph L. Duncan*Chairman

Richard O. AlbrightWalid Abu-Onk Glen Bollin

Robert J. Fluhr Wilbur C. Greer, Jr.Starr D. Kohn

Jerry A. Breite Torbjorn J. LarsenBenjamin Colucci Richard A. McComb, Sr.Michael 1. Darter B. Frank McCullough

The importance of the need for skid-resistant pavement has beenknown for many years. Increased traffic volumes and speeds have in-creased the need for an improved skid-resistant surface. The empha-

sis has been to improve skid resistance by creating new surface tex-tures that increase the macrotexture of the concrete pavement.These textures are created by forming the deeper textures in the plas-tic concrete during the finishing operations. Skid resistance has alsobeen improved in existing concrete pavements by sawing grooves inthe hardened concrete with cutting heads composed of a number of circular diamond saw blades. The traveling public may better under-

stand this as a process of placing a tread in the pavement surface,which complements the tread on the car tires, and stops the vehiclewithout skidding or loss of control by permitting the rapid escape of water.

Keywords: concrete finishes (hardened concrete); concrete finishing (fresh con-crete); concrete pavements; maintenance; measurement; skid resistance; tex-ture.

CONTENTSChapter 1-Need for texture, p. 325.6R-1

1.l-Development of textures1.2-Benefits of texturing1.3-Factors affecting skid resistance

Chapter 2-Texture types, p. 325.6R-32. l-Texturing plastic concrete

2.2-Texturing hardened concrete

Chapter 3-Testing, p. 325.6R-83.1 -Measuring skid resistance3.2-Measuring texture

ACI Committee Reports, Guides, Standard Practices, andCommentaries are intended for guidance in designing, plan-ning, executing, or inspecting construction and in preparingspecifications. Reference to these documents shall not be madein the Project Documents. If items found in these documents

are desired to be part of the Project Documents they should be phrased in mandatory language and incorporated into theProject Documents.

Shiraz D. TayabjiSecretary

Carl P. MeglanJon I. MullarkyThomas J. Pasko, Jr.Robert W. PiggottSteven A. RaganJohn L. Rice*Raymond S. Rollings

Michel Amin SargiousTerry W. ShermanDouglas C. StaabWilliam V. Wagner, Jr.C. Philip Weisz*Gerald E. WixsonWilliam A. Yrianson*

Chapter 4-Maintenance, p. 325.6R-94.1-Snow and ice removal4.2-Retexturing

Chapter 5-Standards related to this report, p.325.6R-9

Chapter 6-References, p. 325.6R-106. l-Cited references6.2-Related references

CHAPTER 1 - NEED FOR TEXTURE1.1- Development of texturesThe importance of the need for a uniform surface

texture to increase skid resistance of both highways andairport pavements has been recognized for manyyears.

The problem of skidding vehicles is not considered to be critical when low volumes of traffic and low speedsare prevalent 3 During the late 1940s and early 1950s,civil engineers raised serious concerns about pavementsafety on the highway system. Increasing traffic vol-umes and speeds, which were contributing to a con-stantly increasing number of accidents and fatalities inthe United States, were the two main factors that ledengineers to believe that pavement skid resistanceneeded to be improved if skidding accidents were to bereduced.

Copyright @I 1988, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or

by any means, including the making of copies by any photo process, or by anyelectronic or mechanical device, printed, written, or oral, or recording for soundor visual reproduction or for use in any knowledge or retrieval system or de-vice, unless permission in writing is obtained from the copyright proprietors.

*Texturing Concrete Pavement Task Group.The committee would like to recognize the contribution made by Martin L.

Cawley for background information and editorial help in preparing this report.

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325.6R-2 ACI COMMITTEE REPORT

During the same period, aircraft runways were being more critically examined in terms of pavement slipperi-

ness. The advent of jet-powered aircraft quickly estab-lished that high-performance airplanes, with accompa-nying higher takeoff and landing speeds, were muchmore difficult to control on wet runways than were pis-ton-type aircraft

Published reports on the adverse effect of pavement

slipperiness on vehicle control go back to the late nine-teenth century. The first concrete street in the UnitedStates, built in Belfontaine, Ohio, had 4 x 4 in. (102x 102 mm) squares formed in the plastic concrete to

provide traction for horses hooves.Grooving hardened concrete pavement appears to

have been a British innovation that was used in 1956 ona number of airfield pavements in England. In theUnited States in the early 1 9 6 0 s the California StateDivision of Highways started sawing grooves in pave-ments to reduce hydroplaning on curves.4

Textures have also been constructed on bridges and

parking-deck ramps by building up a multicomponentepoxy coating system, as indicated in ACI 503.3-79.For many years, pavement texturing in plastic concretehad been accomplished with a burlap drag or a beltdrawn longitudinally along the pavement surface. Dur-ing the late 1960s, deeper texturing efforts were initi-ated. Textures on pavements have been made with bothlongitudinal and transverse patterns using brooms, tin-ing combs or rakes, roller imprints, and a longitudi-nally drawn, coarse polyethylene artificial-turf drag in-verted to provide texture.

The concerns of engineers in developing new deeper

textures in concrete whether in the plastic state or in thehardened state were:

1. The possibility of objectionable pavement noise.2. The possibility of increased roughness, which

would cause objectionable vehicle handling character-istics.

3. Problems associated with vehicles, particularlymotorcycles, experiencing sensations of tracking or loss of handling control of the vehicle on longitudinalgrooves.

4. Increased aircraft-tire wear associated with high-speed landings on deeper textured pavements.

5. Increased pavement wear and rutting.Highway and airport designers have no control over

vehicle speed and tire characteristics, and thereforemust pay attention to the skid resistance of the pave-ment surfaces in their designs. Specifications should beadopted for constructing new portland cement concrete

paveme nt s wi th sa ti sf ac to ry surf ac e te xtur es andcrowns for existing older pavements that have lost their skid resistance.

Cross slopes (or crowns) built into concrete pave-ments, airport runways, and high-speed turnoffs pro-vide for draining the water from the surface rapidly.Generally, a minimum cross slope on highways of 1

percent is recommended. Slopes greater than this can beused provided they are consistent with road safety and

airport runways and taxiways vary from 1 percent to amaximum of 1.5 percent. The cross slopes enhance theskid resistance of textures by proving a good drainagecharacteristic.

1.2 - Benefits of texturingThe results of testing with a standard skid trailer

(ASTM E 274) indicate that transverse textures pro-duce higher friction numbers than longitudinal textures(higher friction numbers indicate greater skid resis-tance). However, it does not necessarily follow thattransverse textures should be used throughout the high-way system, since friction numbers, as measured withthe locked-wheel device, are not sensitive to corneringfriction. It is apparent from studies of grooved pave-ment that longitudinal grooving increases corneringfriction significantly, whereas transverse grooving in-creases mainly longitudinal braking friction. 5 Trans-verse grooves provide a path perpendicular to the di-rection of travel for the escape of water under the tire,which is an important factor in reducing hydroplaning.

The Edens Expressway in Cook County, Ill., wasconstructed as a jointed portland cement concrete

pavement in the early 1950s. The pavement was resur-faced with a bituminous concrete mix in the late 1960s.Between 1979 and 1980, it was reconstructed as a con-tinuously reinforced concrete pavement. The texturingtechnique used in the reconstructed pavement was alongitudinally drawn artificial turf drag followed by atransverse tine device. The positive benefits of surfacetining are reflected in a comparison of the accident sta-tistics compiled for the four years before and after itsreconstruction, as shown in Table 1.2. The northboundlanes were installed in 1979 with tining combs that hadtines spaced at 1/2 in. (13 mm). In 1980, the south-

bound lanes were constructed; however, the tine spac-

Table 1.2 - Statistics compiled by Illinois De-partment of Transportation, District 1 Bureau of TrafficSafety impact of Edens Expressway reconstruction - Four years be-

fore-after comparison of Edens Expressway versus System*

Accidents beforereconstruction:

Accident type 1 1974 to 1977I

Accidents after econstruction: Change,1981 to 1984 percent

59,869 - 3 .93249 - 22.9

181 - 7. 711 - 8 .3

13,677 - 8 .91001 - 22.8

16,470 + 8.9851 - 40.8

7769 + 2.4510 - 40.8

*Chicago Metropolitan Expressway System accident experience excludingEd E

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TEXTURING CONCRETE PAVEMENTS 325.6R-3

ing was changed to 3/4 in. (19 mm) to reduce tearing of the concrete surface. Although a slight increase in noiselevel was anticipated, it was negligible when measuredand actually screened out by other noises. The 3/4 in.(19 mm) tine s pa cing is now standard in Illinois.

The reduction of the wet, snow/ice road surfaceconditions accidents in Table 1.2 shows a very im-

pressive safety impact has been achieved by reducingaccidents. This improvement has been attributed to theimproved surface texture.

Additional benefits observed on pavements with thedeeper textures are: 1) a reduction in water spray fromtraffic due to improved surface drainage, by providingchannels for the expulsion of water at the tire-pave-ment interface into the grooves or deeper striations; 2)a reduction in headlight glare due to the rougher sur-face of the pavement; and 3) a slower buildup of rub-

ber on runways due to airplane touchdowns on groovedairport pavements.

1.3 - Factors affecting skid resistanceSkid resistance of pavements is affected by both themicrotexture of the pavement as related to the sandin the mortar portion of the concrete mixture; and bythe macrotexture, which is defined as the measur-able deeper striations or grooves formed in the plasticconcrete during the finishing operations, or the shallowgrooves cut in the hardened pavement with cuttingheads composed of uniformly spaced circular diamondsaw blades. This report will not discuss microtexture.

The term hydroplaning refers to the separation of tire contact from the pavement surface by a layer of water. This separation causes a loss of steering and braking control of the vehicle. Hydroplaning is a complex phenomenon that is affected by 1) water depth; 2) pavement texture; 3) tire-tread depth; 4) tire-inflation pressure; 5) tire-contact area; and 6) vehicle speed. Anapproximate relationship exists between the speed atwhich hydroplaning will occur and the tire inflation

pressure

\/ ___________

Hydroplane speed = 10.35 tire pressure

when speed is in mph and pressure is in psi.

Some of the earliest investigations and technical reports on loss of vehicle control, which came from the National Aeronautics Space Administration (NASA),were primarily concerned with hydroplaning of aircraftduring wet weather operations. The U.S. Army Air Corps, and its successor the U.S. Air Force, also didvaluable work on this subject. Later, the Road Re-search Laboratory in Great Britain began investiga-tions related to hydroplaning of automobiles. Concur-rent with this research, the Americans and Germansstudied tires and road surfaces to seek their own theo-ries of the factors contributing to skidding. 5

CHAPTER 2 - TEXTURE TYPES2.1 - Texturing plastic concrete

2.1.1 Artificial t u r f texture - This finish (Fig. 2.1.1)2.1.1) may be accomplished by using artificial turf in-

verted and suitably attached to a device that will permitcontrol of the time and rate of texturing. A transverseartificial turf with approximately 2 ft. in contact withthe pavement surface and operated longitudinally in thedirection that the pavement is being placed should berequired. The artificial turf may be weighted to pro-duce a deeper and more uniform texture.

One artificial turf that provides a satisfactory textureis made of molded polyethylene with turf blades ap-

proximately 0.85 in. (21.6 mm) long, and containing7200 individual blades per ft 2 (930 cm 2).

2.1.2 Transverse tine texture - This finish (Fig.2.1.2 ) may be obtained by using a single pass of an ar-tificial turf or burlap followed by a mechanically oper-ated transverse-texturing device. The texturing deviceconsists of a single line of flat, slightly flexible, tem-

pered spring steel tines, spaced at not less than 1/2 in(12.7 mm) nor more than 1 in. (25 mm) centers. Closer centering of the tines will lead to early raveling whilelarger spacing may lead to objectionable road noise.Random spacings have been used on some projects dueto the concern for noise developing from a uniformspacing. The tine width should be 1/8 in. (3.2 mm).Texturing is applied while the concrete is still plastic

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enough to obtain a depth of at least 1/8 in. (3.2 mm) butnot more than 1/4 in. (6.4 mm). The texture is obtained

by one continuous pass of the width of pavement beingtextured. Additional passes or overlapping are not de-sirable because they create weak narrow ridges of mor-tar that will break easily under traffic.

2.1.3 Longitudinal tine texture - The longitudinaltine texture (Fig. 2.1.3) is accomplished with the same

basic materials, equipment, and care as the transversetine texture, except that the tines are pulled in a line

parallel with the centerline of pavement.

2.1.4 Transverse broom texture - This finish (Fig.2.1.4) may be obtained by using a mechanically oper-ated transverse broom finishing device. The broomconsists of multiple rows of stiff bristles capable of

producing striations 1/16 to 1/8 in. (1.6 to 3.2 mm) deepin the plastic concrete. The striations are uniform inappearance with a spacing approximately equal to their depth and are transverse to the pavement centerline.

2.1.5 Longitudinal broom texture-

The longitudi-nal broom texture (Fig. 2.1.5 ) is accomplished with thesame basic materials, equipment, and care as the trans-

Fig. 2. 1 .2- Transverse tine texture

Fig. 2.1.3-Longitudinal tine texture

Fig 2 1 4- Transverse broom texture

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verse broom finish except that the brooms are operatedin a direction parallel to the pavement centerline.

2.1.6 Transverse tine with longitudinal artificial t u r f textur e - The transverse tine texture preceded by thelongitudinal artificial turf finish (Fig. 2.1.6) is recom-mended for high-speed highways or where sudden ac-celeration or deceleration (panic stops) may occur. Thetransverse texture provides 1) a better drainage pattern;

2) improved initial skid resistance in a longitudinal di-rection; 3) a longer lasting texture due to deeper valleysas compared to the broom; and 4) a slight improve-ment in cornering control provided by the initial pass of longitudinal artificial turf. A longitudinal tine texturecould be used on areas such as curves where corneringforces are required. Other textures may be appropriateon low-speed roads or city streets and highways; they

provide satisfactory initial skid resistance, but they willwear smooth at an earlier age.

2.1.7 Friction numbers of textures - Table 2.1.7 , for friction numbers at 30, 40, and 50 mph, indicates thatthe best results were obtained by the various textures asfollows. 7 The results are listed from highest (best) tolowest:

1. Longitudinal artificial turf and transverse tine2. Transverse tine

3. Transverse broom4. Longitudinal artificial turf 5. Longitudinal tine6. Longitudinal broom

The values were obtained when the various surface tex-tures were tested in accordance with ASTM E 274 for alocked-wheel skid trailer.

The following graphs illustrate the changes in fric-

tion numbers obtained in October, 1976 (when con-structed) and for three succeeding years for each of thetextures constructed in plastic concrete. Fig. 2.1.7(a)and 2.1.7(b) are plotted for regular (treaded) tires at 40mph from data listed in Table 2.1.7.

2.1.8 Factors affecting pavement texture - Thedepths obtained with the various types of texturing in

plastic concrete depend upon the timing of the textur-ing operation. Therefore, field-inspection personnelshould work with the contractor to achieve the desireddepth of texture. Because timing is critical, it is recom-mended that the texturing machine be a separate piece

of equipment. Combining this operation with another one, such as a membrane-curing machine, may delaythe texturing until less than desirable depths of textur-ing are obtained. The benefit of the deeper texture islonger service life, assuming studded tires are not per-

Fig. 2.1.5-Longitudinal broom texture

Fig 2 1 6 Transverse tine texture with longitudinal artificial turf texture

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Table 2.1.7 - Friction number at 30,40 and 50 mph (Reference 7)Texture FN30 Range

Transverse tine andartificial turf (longitudinal)

10-05-7607-18-7710-24-7704-24/25-78 Reg.*04-24/25-78 Slic10-10-78 Reg.10-10-78 Slicks07-06-79 Reg.07-06-79 Slicks10-19-79 Reg.10-19-79 Slicks

676361575661605552

68717571625862616562

Transverse tine10-05-7607-18-7710-24-7704-24/25-78 Reg.04-24/25-78 Slicks10-10-78 Reg.10-10-78 Slicks07-06-79 Reg.07-06-79 Slicks10-19-79 Reg.10-19-79 Slicks

79 __

62676154574758545747

65687261615061566156

Transverse broom10-05-7607-18-7710-24-7704-24/25-78 Reg.04-24/35-78 Slicks10-10-78 Reg.10-10-78 Slicks07-06-79 Reg.07-06-79 Slicks10-19-79 Reg.10-19-79 Slicks

69 __

61626129532555335329

66707340613765376239

Artificial turf (longitudinal)10-05-7607-18-7710-24-7704-24/25-78 Reg.04-24/25-78 Slicks10-10-78 Reg.10-10-78 Slicks07-06-79 Reg.07-06-79 Slicks10-19-79 Reg.10-19-79 Slicks

68 __

57636033543158395429

64657348614562466439

Longitudinal tine10-05-7607-18-7710-24-7704-24/25-78 Reg.04-24/25-78 Slicks10-10-78 Reg.10-10-78 Slicks07-06-79 Reg.07-06-79 Slicks10-19-79 Reg.10-19-79 Slicks

66 __

61646156565461535848

62647064584762596050

Longitudinal broom10-05-7607-18-7710-24-7704-24/25-78 Reg.04-24/25-78 Slicks10-10-78 Reg.10-10-78 Slicks07-06-79 Reg.07-06-79 Slicks

*Reg.,, denotes treaded tires ; slicks are smooth or nontreaded tires.

Lane 2 Lane 1 Lane 2 Lane 1

__ 69-87 __

62-6965-6961-6756-6555-6152-6160-6454-6552-5848-53

65-7268-7473-7866-7661-6555-6158-6557-6663-6859-65

71 __

62645651544857545346

72-86 __

61-6464-6959-6440-6155-6042-5554-6438-6153-6139-53

62-7064-7368-7545-7259-6436-5459-6444-6458-6443-63

65 __

56615645543956435341

60-74 __

56-6759-6659-6225-3148-5523-2753-5729-3751-5524-31

53-7168-7371-7733-4656-6434-3963-6732-4060-6432-42

61 __

53595221511952274921

61-78 __

47-6362-6654-6327-3950-5924-4056-5928-5151-5725-37

60-6761-6866-7834-6159-6435-5060-6538-5262-6529-44

55 __

48525123492150274921

60-72 -

53 __

56-67 55-66 5461-68 62-68 5858-66 66-72 5345-61 51-74 3654-59 56-59 5249-57 39-55 4058-64 60-63 5945-58 53-62 4954-60 59-62 5537-54 42-56 41

65 __ 52-76 __

56 60 52-6162 63 58-6461 71 55-6331 42 29-3355 59 53-5835 39 31-3860 63 58-6136 38 34-39

57-6460-6668-7336-4758-6035-4461-6535-44

52 __ 4957492353215328

67687166605463606457

58636660564459535950

57646542562660306032

55586538563160355726

54596548543959505640

5156622853266126

Range FN 60 Range ____ ___ Lane 1 Lane 2 Lane 1

62-77 __

61-6462-6754-5846-5752-5546-4955-5848-5751-5743-49

63-7166-7069-7461-7358-6245-5761-6458-6260-6850-60

62 __

57595347504653505041

59-73 __

53-5957-6352-5829-5552-5523-4554-5828-5250-5527-47

54-6060-6563-6846-6653-5831-5056-6245-5857-6234-55

56 __

51555035513552434736

56-66 __

48-5756-6251-5417-2548-5318-2249-5422-3046-5318-23

50-6260-6759-6936-4855-5723-3058-6122-3957-6228-38

50 __

45534514461548224416

42-65 -

42 __

40-50 48-60 4048-58 54-64 4946-57 60-68 4315-33 29-48 1644-54 53-58 4418-27 23-34 1650-51 57-61 4721-34 23-41 2447-54 53-60 4417-26 22-34 16

46-60 __

47-6052-6349-5922-5048-5533-4757-6141-5552-5730-48

46-6055-6262-6728-5850-5731-4658-6142-5553-5828-48

45 __

47544838493552394934

43-65 __

46-5255-5945-5219-4052-5418-2349-5626-31

45-5654-5961-6423-3049-5622-3359-6422-29

37 __

4350441445204820

Lane 2

63646857585161586052

56596249534056435444

50566121512254255424

46515424492554265023

48525841493157435031

4649551748215621

Lane 1 Lane 2

53-74 __

54-5956-6152-5545-5048-5439-5050-5548-5148-5438-44

60-6861-6966-6948-6456-5944-5758-6544-6257-6149-55

52-61 __

45-5353-5847-5326-4248-5418-4050-5429-4945-4925-43

53-6254-6258-6436-5950-5531-4754-5830-5349-5729-49

45-55 -

39-53 42-5251-55 54-5940-47 57-6312-18 14-2845-47 50-5313-18 18-2644-50 51-5719-26 21-3342-46 53-5614-20 16-27

38-48 __

31-4742-5739-4610-2538-4813-2243-5218-3041-479-19

41-5049-5351-5915-3446-5218-3249-5721-3447-5517-28

39-57 __

36-5349-5846-5125-4545-5224-4149-5630-4546-5224-41

41-5646-5754-6122-5945-5123-4553-6034-5946-5321-41

35-41 __

38-4946-5242-4512-1642-4715-3245-5018-23

41-4847-5153-5714-2146-5018-3054-5817-23

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65

64

63

62

61

60

59

56

57

56

55

54

53

52

51

50

49

1976 1977 1976 1979

__

CALENDAR YEARS

__ Fig. 2.1.7(a)-Friction number changes: Various textures ( ^ = transverse tine; X = longitudinal tine; \/ = transverse broom)

70

66

66

56

54

52

50

46

1976 1977 1976 1979

CALENDAR YEARS

Fig. 2.1.7(b)-Friction number changes: Various textures = longitudinal broom; = transverse tine and longitudinal turf; = artificial turf [longitudi-nal])

mitted on vehicles using the road. There is no knowntexture that can survive wear in the tire paths caused bynormal volumes of traffic using studded tires.

Rain on a pavement surface during construction mayobliterate the texture if the concrete has not hardened

sufficiently.8

This can be corrected by grinding the pavement and grooving the concrete in the hardenedstate by the use of diamond-blade saws. Leaving a rain-d d d ill f

cially during rain, snow, or icing conditions, which maycause an operator to lose control of his or her vehicle.

2.2 - Texturing hardened concreteSkid resistance on worn, polished, contaminated, or

slippery hardened concrete may be improved by severalmethods, including diamond grinding and/or groov-ing, sandblasting, waterblasting, or chemically treating

f h f S dbl i h i l

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Fig. 2.2.2-Diamond saw-blade texture

improved texture, better drainage, greater skid numbers and a longer life with improved skid resistance.

2.2.1 Groove patterns - Sawed groove patterns for highways should be not less than 1/8 in. (3.2 mm) wideor more than 1/4 in. (6.4 mm) deep and centered at notless than 1/2 in. (13 mm) nor more than 1 in. (25 mm).

Highway grooving may be transverse or longitudi-nal. The transverse grooves are cut at 90 deg to thecenterline of the pavement while the longitudinalgrooves are cut parallel to the centerline of the pave-ment.

Generally, transverse grooving is recommended for highways, particularly where frequent braking action is

required. The exception might be on curves or heavilytraveled highways. However, the interference to trafficcaused by closing more than one lane at a time, alongwith the greatly increased time to groove the pavementand increased cost, has resulted in longitudinal groov-ing being used in lieu of transverse grooving. Trans-verse textured surfaces tend to be noisier than longitu-dinally textured surfaces when the textures are new. Asthe surfaces experience traffic wear, the variations be-tween the noise levels decrease and are insufficient torule out their use as a final finish. 7

For airports, the Federal Aviation Administration of

the U.S. Department of Transportation recommendsthat the sawed-groove pattern on runways should betransverse (perpendicular to the direction of aircraftmotion). The grooves should be 1/4 in. (6.4 mm) wide

by 1/4 in. (6.4 mm) deep with center-to-center groovespacing not less than 1 1/8 in. (28.6 mm) nor more than2 in. (50.8 mm). 9

2.2.2 Reprofiling pavements - Before texturinghardened concrete, particularly in areas where studdedtires are permitted, field checks should be made to de-termine whether ruts have been worn in the pavementsurface, creating water channels and making hydro-

planing very probable. A suggested method of reprofil-ing pavements is the use of a multiple diamond saw- blade grinding machine. These machines have been de-

l d f ll h l

CHAPTER 3 - TESTING3.1 - Measuring skid resistance3.1.1 Airport pavements - The skid resistance of airport pavements is measured by the British Mu-Me-ter (ASTM E 670) which is used throughout theworld. It is a simple device and consistent when used onlevel, tangent sections of pavement and has the mobil-ity needed to take measurements with a minimumamount of runway downtime. 9

3.1.2 Highway pavements3.1.2.1 Skid trailer - Surface friction-number

measurements of highway pavements in the UnitedStates are typically made using a locked-wheel skidtrailer that meets the requirements of ASTM E 274.This procedure measures the frictional force on alocked test wheel as it is dragged over a wet pavementsurface under constant load and a constant speed, withits major plane parallel to the direction of motion and perpendicular to the pavement. The standard referencespeed is usually 40 mph, and the results are expressedas a friction number (FN). Well-textured new pave-ments will have friction numbers above 60 when testedat a speed of 40 mph.

3.1.2.2 British pendulum - The British pendulumdevice (ASTM E 303) has also been used to measure

surface friction properties. A number of other deviceshave been used, including the diagonal brake vehicle,Swedish skiddometer, James brake decelerometer, andthe Miles friction trailer.

3.2 - Measuring texturePavement textures are complex, and therefore ef-

forts at correlating skid resistance with texture mea-surements have had marginal success. There are manydifferent proposed methods for measuring pavementtexture. All attempt to set some minimum value that

would produce an acceptable macrotexture.10

They allgive a measurement of the average texture depth. Thesand-patch test, the NASA grease smear technique, theili i d i ( fl ) d

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3.2.1 Sand patch test - A measured amount of sandis poured on the pavement and the pile is carefullyspread over the surface to form a circle. The texturedepth of the surface is then determined from the diam-eter of the circle of sand.

3.2.2 NASA grease smear technique - A measuredamount of grease is placed on the pavement and spread

on the pavement between two lines of masking tape 4in. (102 mm) apart. The grease is then worked into thevoids of the pavement with a rubber squeegee, withcare taken that no grease is left on the tape or squee-gee. The distance along the taped lines is measured andthe area is then computed. 9

3.2.3 S ilicone putty test - A known volume of sili-cone putty is formed into an approximate sphere and

placed on the pavement surface. A recess in a plate iscentered over the putty, and the plate is pressed downin firm contact with the surface. The average diameter of the deformed putty is recorded.

3.2.4 Static drainage (outflow meter) test - A spec-ified-size cylinder with a rubber ring glued to its bot-tom face is placed on the pavement surface and loadedso that the rubber ring will drape over the aggregate

particles, similar to that expected of tire tread ele-ments. Water is poured into the cylinder, and the timerequired for a known volume of water to escapethrough the pavement and between the rubber ring andsurface is measured. 10

3.2.5 Stereophotograph test (E 770-80) - The ster-eophotographs of the pavement surface are viewedthrough a transparent grid with a 10 x 10 mm grid. The

six texture parameter numbers for each of ten randomcentimeter-squares are noted. The texture parameter number of the pavement photograph is the average of the parameter number of the ten squares.

CHAPTER 4 - MAINTENANCE4.1 - Snow and ice removal

Pavements that are located in areas with snow or ic-ing conditions, and which require deeper textures toobtain higher skid resistance, may require an increased

maintenance effort to remove the snow and ice. Snow- plows may experience more rapid wear of the plow blades. Windblown snow tends to accumulate more ondeeper textures, especially when the wind is blowing ina direction which is at right angles to the striations of the texture. In some cases, increased quantities of snow-removal chemicals will correct the condition. Al-though concern has been expressed by some observersthat the increased use of deicing chemicals on pave-ments with the deeper textures may cause earlier dete-rioration (especially in areas adjacent to curb and gut-ter sections and on bridge decks adjacent to the curb

sections where brine accumulations may occur), this hasnot been verified by field observation. Salt-exposurelaboratory tests on properly air-entrained concrete in-

4.2 - RetexturingLarge areas of smoother textures, such as those

caused by rain damage in plastic concrete surfaces,have been reported to ice up faster than areas withdeeper textures, thereby lowering the friction number.Drivers traveling from a new section of pavement withthe deeper textures onto a rain-damaged pavement, or to an older pavement surface where the surface texturehas been worn smooth, may experience inferior ve-hicle-handling characteristics. This is particularly truein rainy, snowy, or icing conditions. These areas can becorrected by grooving the older pavement with multiplediamond saw-blade grinding or grooving machines.

CHAPTER 5 - STANDARDS RELATED TO THISREPORT

The documents of the various standards-producingorganizations referred to in this document are listed below with their serial designation, including year of adoption or revision. The documents listed were thelatest effort at the time this document was written.Since some of these documents are revised frequently,generally in minor detail only, the user of this docu-ment should check directly with the sponsoring groupif it is desired to refer to the latest revision.

American Concrete Institute503.3-79(Reapproved 1986)

Standard Specification for Pro-ducing a Skid-Resistant Surfaceon Concrete by the Use of aMulti-Component Epoxy System

ASTM E 274-85

E 303-83

E 501-82

E 524-82

E 556-82

E 660-83

E 670-85

Standard Test Method for SkidResistance of Paved Surfaces Us-ing a Full-Scale TireStandard Method for MeasuringSurface Frictional Properties us-ing the British Pendulum Tester Standard Specification for Stan-dard Tire for Pavement Skid-Re-

sistance TestsS t a n d a r d S p e c i f i c a t i o n f o r Smooth-Tread Standard Tire for Special-Purpose Pavement Skid-Resistance TestsStandard Method for Calibratinga Wheel Force on Torque Trans-ducer Using a Calibration Plat-form (User Level)Standard Practice for Acceler-ated Polishing of Aggregates or P a v e m e n t S u r f a c e s U s i n g a

Small-Wheel , Circular Track Polishing MachineStandard Test Method for SideF i i P d S f U i

8/13/2019 3256r_88

10/10


E 707-79 Standard Test Method for Skid(Reapproved 1984) Resistance of Paved Surfaces Us-

ing the North Carolina State Uni-versity Variable-Speed FrictionTester

E 770-80 Standard Test Method for Clas-(Reapproved 1985) sifying Pavement Surface Tex-

turesE 965-83 Standard Test Method for Mea-

suring Surface MacrotextureDepth Using a Sand VolumetricTechnique

These publications may be obtained from the follow-ing organizations:

American Concrete InstituteP.O. Box 19150Detroit, MI 48219-0150

ASTM1916 Race St.Philadelphia, PA 19103

CHAPTER 6 - REFERENCES6.1 - Cited references

1. Murphy, William E., The Skidding Resistance of ConcretePavements: A Review of Research, Development and Practice in theUnited Kingdom, Roadways and Airport Pavements, SP-51 , Amer-ican Concrete Institute, Detroit, 1975, pp. 231-256.

2. Guidelines for Texturing of Portland Cement Concrete Pave-ments, Technical Bulletin No. 19, American Concrete PavementAssociation, Arlington Heights, 1975, 13 pp.

3. Davis, J. L.; Ledbetter, W. B.; and Meyer, A. H., Final Re- port on Concrete Experimental Test Sections in Brazos County ,Texas, Research Report No. 141-4F, Texas Transportation Insti-tute, College Station, 1974.

4. A Guide to Highway Grooving, General Electric, Worthing-ton, Ohio.

5. Gallaway, B.M.; Ivey, D. L.; Ross, H. E., Jr.; Ledbetter, W.B.; Woods, D. L.; and Schiller, R. E., Jr., Tentative Pavement andGeometric Design Criteria for Minimizing Hydroplaning, Repo rt

No. FHWA-RD-79-3 1, Federal Highway Administration, Washing-ton, D.C., 1979.

6. Standard Specifications for Road and Bridge Construction,Illinois Department of Transportation, Springfield, Oct. 1983, 238

pp.7. Dierstein, Phil G., A Study of P.C.C. Pavement Texturing

Characteristics in Illinois, IDOT Physical Research Report No. 95,Illinois Department of Transportation, Springfield, 1982, 54 pp.

8. Interim Guidelines for Protection and Acceptance of ConcretePavements Exposed to Rain During Construction, Technical Bulle-

tin No. 17, American Concrete Pavement Association, ArlingtonHeights, 1974, 11 pp.9. Methods for the Design, Construction, and Maintenance of

Skid Resistant Airport Pavement Surfaces, Advisory Circular No.150/5320-12, Federal Aviation Administration, Washington, D.C.,1975, 73 pp.

10. Rose, J. G.; Hutchinson, J. W.; and Gallaway, B. M., Sum-mary and Analysis of the Attributes of Methods of Surface TextureMeasurement ," Skid Resistance of Highway Pavements, STP-530,ASTM, Philadelphia, 1973, pp. 60-77.

11. Chamberlin, William P., and Amsler, Duane E., MeasuringSurface Texture of Concrete Pavements by the Sand-Patch Method,

Report No. FHWA-NY-78-RR62, New York State Department of Transportation, Albany, 1978, 18 pp.

6.2 - Related references12. Skid Resistance, NCHRP Synthesis No. 14, Highway Re-

search Board, Washington, D.C., 1972, 66 pp.13. Guidelines for Skid Resistant Pavement Design, American

Association of State Highway and Transportation Officials, Wash-ington, D.C., 1976, 20 pp.

14. Ryell, J.; Hajek, J. J.; and Musgrove, G. R., Concrete Pave-ment Surface Textures in Ontario - Development, Testing and Per-formance, pap er pre sented at Transpor ta ti on Res ear ch Board ,Washington, D.C., Jan. 1976.

15. Skidding Accidents-Pavement Characteristics, Transpor-tation Research Record No. 622, Transporta tion Research Board,1977, 110 pp.

16. Balmer, G. G., The Significance of Pavement Texture, Re- por t No. FHWA-RD- 75-12, Fed era l Highway Administ rat ion,

Washington, D.C., 1975, 44 pp.17. Interim Report for Runway Rubber Removal Specification

Development: Field Evaluation Results and Data Analysis, Repo rt No. DOT/FAA/PM-85/32, Federal Aviation Administration, Wash-ington, D.C., July 1984-July 1985, 106 pp.

18. Rubber Removal Specification Development-Final Re- po rt , Report No. DOT/FAA/PM-85/33, Federal Aviation Admin-istration, Washington, D.C., May 1983-Sept. 1985, 51 pp.

This report was submitted to letter ballot of the committee and wasapproved in accordance with ACI balloting procedures.