Highway Administration

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1 and One-Year Evaluation Installation No. 8 Aggregate Seal and of W. Payne Charles Technician Supervisor Materials opinions, findings, and conclusions expressed in this (The are those of the author and not necessarily those of report Highway & Transportation Research Council Virginia Cooperative Organization Sponsored Jointly by the Virginia (A of Highways & Transportation and Department University of Virginia) the Cooperation with the U. S. Department of Transportation In Highway Administration Federal 1984 February 84-R25 VHTRC Precoated Chip Seal by the sponsoring agencies.) Charlottesville, Virginia

2 MAINTENANCE RESEARCH ADVISORY COMMITTEE R. L. MOORE, Chairman, Resident Engineer, VDH&T M. G. ALDERMAN, Senior Traffic Engineer, VDH&T J. G. BROWDER, JR., Assistant District Engineer, VDH&T C. M. CLARKE, Assistant District Engineer- Maintenance, VDH&T R. H. CONNOCK, JR., Assistant District Engineer, VDH&T J. A. COPP, Residency Maintenance Supervisor, VDH&T C. F. GEE, Resident Engineer, VDH&T J. W. HINCHER, Resident Engineer, VDH&T J. L. HOLTZ, Program Systems Development Supervisor, VDH&T C. O. LE!GH, Maintenance Engineer, VDH&T D. C. MAHONE, Highway Research Senior Scientist, VH&TRC D. H. MARSTON, Assistant District Engineer- Maintenance, VDH&T J. C. MCCABE, Area Engineer Lynchburg-Staunton, FHWA J. K. MCEWEN, Assistant Maintenance Engineer, VDH&T J. E. MELONE, Equipment Engineer, VDH&T C. B. PERRY II, Resident Engineer, VDH&T D. S. ROOSEVELT, Resident Engineer, VDH&T B. W. SUMPTER, Assistant District Engineer, VDH&T M. B. VANN, Assistant Construction Engineer, VDH&T J. H. WILLIAMS, Assistant District Engineer- Maintenance, VDH&T W. E. WINFREY, Materials Engineer, VDH&T ii

3 report describes the placement and ear, erformance of This test sections on which No. 8 modified urry seal and experimental No. 8 chip seal surface treatments were placed. From precoated made during the installation and the performance after observations one it is concluded that the No. 8 modified slurry seal treatment has year, potential but that use of the No. 8 chip seal treatment is not good ABSTRACT feasible. iii

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5 and One-Year Evaluation Installation No. 8 Aggregate Seal and of W. Payne Charles Technician Supervisor Materials effectiveness of the methods being employed. As part of this the for the past several years the Staunton District has been effort, district with test installations placed on driveways and parking the it was decided to place some test sections of these materials on areas, lightly trafficked, rural, 4-1ane divided highway. As mentioned in a original working plan for the experiments by Mahone, the test the the general purpose of the project was to determine the While of using the seal treatments in the repair of bituminous feasibility pavements, some of the specific objectives were to-- increase the crack-sealing capabilities of a slurry seal with I. more fluid mixture of No. 8 stone and emulsified asphalt the improve the skid resistance of a slurry seal with the coarse 2. provided by the No. 8 slurry seal, texture provide an alternate surface treatment that could be employed 4. for surface treating and patching over a longer season both is possible with conventional chip seal treatments, which than a tendency to lose aggregate in cold weather. have Precoated Chip Seal by INTRODUCTION of the increased cost of maintaining Virginia's roadway Because there is a continuing effort to lessen the expense and improve system, with slurry seal treatments using No. 8 stone and chip experimenting using precoated No. 8 stone. In view of the success achieved by seals sections were to be monitored for 3 years after placement.(1) PURPOSE AND SCOPE as compared to the finer type B slurry seal, reduce the potential for dust and flying stone that are 3. of conventional seal treatments, and characteristic

6 site selected for the study was a 4.12-mile (8.19-km) portion The Route ii in Rockbridge County that was built in In the original on this section since 1952 are shown in Appendix A. The surfaces in below the experimental seals are noted in Table I. immediately determine the structure of the pavement prior to and after To of the experimental test sections, the Research Council's placement tester was used. These results will be shown and discussed dynaflect in the report. later B 1974 NB B 1973 SB i B 1973 NB B 1974 SB NP 1977 NB i0.83-ii.22 B 1973 SB existing surface mixes were an S-5, a slurry-b, and an 1-2 non- The mix that had outlived their service lives and were badly polishing Much of the surface texture was worn off and there were deteriorated. cracks in both the S-5 and slurry seal, as can be seen in considerable Figures I, 2, and 3. PRELIMINARY INVESTIGATION Pavement Structure the subbase was 4 to 6 in. (I0 to 15 cm) of select local pavement, the base 5 in. (12.5 cm) of waterbound macadam plus 3 in. (7.5 borrow, of bituminous penetration, and the surface I to 3 in. (2.5 cm to 7.5 cm) of H-2 bituminous concrete. The drainage is good. The mixes placed cm) Table 1 Mix Types of Pavement Surface Prior to Placement of Test Sections Milepo.st M.i X.Type Year of.placement.lan.e S NB/SB Pavement Condition

7 Figure I. S-5 mix. Figure 2. seal.

8 Figure non-polishing mix. portion of Route Ii selected for the experimental sections The from milepost 6.10 (south end of Fairfield) to milepost extends of 1-81 interchange) and traverses slight curves and grades. The (south in Appendix B show the tangent and curve sections as well as sketches average daily traffic volumes obtained from the Department for The the year the test sections were placed, and the 2 prior years 1982, Site Geometrics positive and negative grades. Traffic Volumes showed no increases, as can be seen in Table 2. (2) 4

9 Daily Traffic Volumes 1, , , ,980-4% 1981 determine if the section of pavement between mileposts 6.10 and To was prone to wet weather accidents, the accident reports covering year period were reviewed and revealed that only 3 of the total of a reported accidents had occurred while the pavement 26 wet (see was Wet % Total Milepost Accidents Accidents Wet Year I ii 1 9 Total rainfall and temperature data for the period Monthly were from Lexington, the closest weather station, and obtained shown in are Table 2 Single Unit year Cars Trucks Buses ADT Change , ,070 0 Wet Weather Accidents Table 3). Table 3 Wet Weather Accident Data Cli...mato l..0.gic.data_ C. Data for the days that the test site were placed will be Appendix later in the report. shown

10 the summer and fall of 1982, precoated No. 8 surface treat- During and No. 8 slurry seal test sections were placed on all four lanes ment Route 11 between mileposts 6.10 and The surface treatment of was chip seal consisting of a CRS-2H (SBL) and CRS-2 (NBL) and No. 8 a emulsions) and No. 8 polish-resistant quartz instead of the (cationic slurry seal aggregate gradation. Table 4 shows the amount of fine Type... of Emulsion CRS-2H CSS-IH and quick setting emulsifying agents were used in the Solvents and mixing agents were used in the CSS-IH. CRS-2H, non-polishing No. 8 river gravel used for the precoated chip The and the non-polishing quartzite used in the No. 8 slurry mix both seal No. 8 Precoated 8 Mix No comparative purposes, two sections of the state's conventional For seal B and a chip seal consisting of CRS-2H asphalt and polish- slurry aggregate from the Lone Jack Quarry were placed. Figure 4 resistant a layout of all the test sections and dates of placement. shows SECTIONS TEST Materials river gravel with approximately 1.4% to 1.7% AC20 asphalt. non-polishing modified slurry seal consisted of a blend of CRS-2H and CSS-IH The residue and viscosity of the emulsions used in the No. 8 slurry mix. Table 4 Emulsions Asphalt Residue, % Viscosity came from Lone Jack Quarry. The gradations are shown in Table 5. Table 5 Sieve Analysis in Percent Passing Indicated Sieves Test Section 3/8 No. 4 No. 8-8 No. 200

11 ,4 O0"L o -,,-I n o,,i.i 00"6 o

12 precoated and conventional chip seals were put down with state The and equipment, except that a self-propelled chip spreader forces was from John Hall Construction Company in Roanoke. The equipment rented of a tanker distributor calibrated prior to use, a tractor consisted a front-mounted broom, a rubber-tired roller, and the necessary with signs, and barricades for the operation. trucks, Pavers, Inc. of Richmond placed the No. 8 modified and slurry seals. The No. 8 slurry was placed in August using conventional standard slurry paver but because of the size of the stone, the second a placed in October, was put down with a box specially application, for use with a Midland Cold-mix paver (see Figures 5 and 6). designed rear of the cold-mix machine was modified to The high pressure pumps use ensure mixing of the asphalt and stone. Also, the spreader box had to modified to eliminate spillage of the material. Originally, the been box had an auger in both the front and rear to evenly distrib- spreader the material; however, the rear auger was removed to eliminate ute spillage of material onto slurry already placed on the pavement. pavement was 24 ft. (720 cm) wide in each direction, which The no problem for the slurry machine or cold-mix paver in placing the posed No. 8 slurry, since they both would spread to a 12 ft. (360 cm) modified However, when placing the precoated chip seal, three passes with width. the 8 ft. (240 cm) chip spreader were necessary. application rates for the treatments are shown in Tables 6 and The and the daily air and surface temperatures for the days of placement 7, Installation in Table 8.

13 Figure 5. Spreader box on Midland paver. Figure 6. Placing No. 8 slurry with Midland paver.

14 ii Application Rates for No. 8 Seal Milepo, st SBPL SBPL I SBTL SBTL I NBPL I NBTL i0.87- Application Rates for Precoated Chip Seal M.ileP0st Lane 8' Section Gal./Yd. I0 NBTL Outside I0 NBPL Inside i0 NBTL-PL Middle SBTL Outside SBPL Inside SBTL-PL Middle Lb. yd Table 6 L.ane Date I NBPL 3O I Note: I lb./yd. = 0.54 kg./m 2. Tab le 7 Lb./Yd. Date 1 gal./yd i/m. 2; i lb./yd kg./m.2 NOTE" 10

15 a.m :30 a.m :30 a.m :30 a.m :30 p.m :30 p.m :30 p.m "50 p.m :45 5:00 p.m a.m :50 a.m I0:00 a.m. 78 I00 ii:i0 a.m :50 p.m. 82 I01 12:50 p.m :50 p.m :50 p.m :30 a.m i0:00 a.m II:00 p.m :35 p.m :30 p.m :30 p.m :30 a.m :55 a.m ii:35 a.m :05 m :00 p.m i:00 p.m :45 p.m :50 p.m :42 a.m :25 a.m i0:20 a.m I0:52 a.m II:43 p.m :20 p.m :20 Table 8 Temperature Data, Degrees F. Surface Date Time Air NOTE: 5/9 (Deg. F -32) Deg. C. 11

16 tests were run prior to and after placement of the experi- Skid surfaces, and w±ll be made yearly for the 3-year evaluation mental Append±x D shows the mean skid data from tests with both bald period. treaded t±res on the old slurry seal and new surfaces. The skid and for the precoated chip seal and No. 8 slurry range from the 40's numbers the 60's, which is quite satisfactory. to determine if there was any significant improvement in the ride To tests were conducted with the Mays meter prior to and after quality, of the test sections. Based on the Mays meter rating scale placement in a report by McGhee(3), and shown in Table 9, the new surfaces given not produce any significa--nt improvement in ride quality. The did data can be seen in Table i0. roughness _R ide Meter Rating Scale Mays McGhee 3 ) (After Skid Tests Ride 0u.alitY Table 9 Mays Roughness, In./Mi. Qu.a! i..t.y Very Rough Rough Rough Slightly Average Smooth 70 NOTE" 1 in./mi cm./km. 12

17 Chip Seal Precoated Chip Seal Precoated Chip Seal Precoated Chip Seal Precoated Chip Seal Conventional Chip Seal Conventional Chip Seal Conventional Chip Seal Conventional 8 Modified No. 8 Modified No. 8 Modified No. 8 Modified No. Before M lepost Lane NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL 8.77-ii NBPL SBTL 8.77-ii SBPL After structural evaluation of the pavement was carried out with the The dynaflect tester. Based on Figure 7 in Vaswani's report Council's This is shown in Figure 7 by the broken lines. The soil support 8.8. is found in Vaswani's report "Recommended Design Method for value Pavements in Virginia,"(5) and the daily traffic in 18-kip Flexible is calculated as equivalents NI8 0.88(35) (10) (80) (15) I0 Table Mays Meter Roughness Data, In./M. Site NOTE: 1 in./mi cm./km. Structure Pavement "Design Guide for Secondary Road Pavements in Virginia,"(4) the entitled index for the amount of traffic the roadway carried should be thickness 0.88 NTT N3A N N B, or A 6T 13

18 !! t. L l..... g. enl' A ouetitsebi x t td = enl' A oddns [To S 14

19 Table II it can be seen that a structure of the pavement was From adequate for the traffic it carried, since the thickness index not that the chip seals did a poorer job of sealing the pavement suggest did the No. 8 slurry seal. than the goal of this evaluation was to assess the performance Because the No. 8 slurry seal and precoated No. 8 chip seal, this report is of an installation report against which subsequent performance basically be judged. Some of the observations and conclusions during con- can The operations of both the state forces and Richmond I. were efficient. Traffic was controlled to allow the Pavers The application rates for both seal treatments were kept close 2. the desired rates. However, it can be noted back in to Even though the above observations suggest a good job, the 3. of both treatments has been poor. Although the performance recently laid test sections were closed to traffic to most them to cure for a sufficient time, neither performed allow when opened to traffic. While the precoated stone and well adhered well to each other, the materials picked up asphalt badly under traffic. Flying stone broke the windshields very a number of cars. Loose stone had to be swept from the on several times, but after a couple of days the stone pavement to adhere and the treatment looked good. One of the began started, as well as at the center joint. The problem another these points was that the material overlapped and created a at The fines were not dry, did not produce uniform spreader. and packed down to produce a poor riding surface coverage, rolled. The pavement was swept several times, but some when the material remained until it was washed off. As the of read 8.8 or above and none of the readings before placement of should test sections exceeded 6.5. Also it is noted in this table that in the places thickness indices were worse after the installation than some This is probably attributable to subgrade moisture, which would before. OBSERVATIONS AND CONDITIONS struction are listed below. test sections ample curing time. 6 that the No. 8 slurry was applied at an average of Table lb./yd.2 (13.5 kg/m2). 30 with the slurry seal was poor lap joints. Too much problems was left at the joint where one shot ended and material thickness that resulted in a rough riding surface and double excess material to be bladed off by snowplows, which left raveling problems. Another problem during installa- created was poor application of the fines by the rotary type sand tion material broke up and came off it pulled off some of remaining slurry with it. the 15

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21 The test sections were observed in the spring of 1983 and 4. was performing well. Some of the stone was stripping neither the chip seal section and much of the material was off off the slurry seal. raveling investigation has shown that further work with the No. 8 The slurry is essential. It is believed that this type of seal modified to date can be solved. In 1983, the No. 8 modified slurry was ments on three roads in the Staunton District with good success, and at placed end of the year were performing well. A report on the 1983 test the will be made later. sections regard to the precoated No. 8 chip seal, in light of the poor In of applications that have been placed in parking lots and performance the experiments are (I) that use of the No. 8 slurry seal treatment from feasible, but modifications must be made and more test sections must is Recommendations for Further Study has the potential of adequately preserving Virginia's roadways treatment can produce a durable surface if problems encountered in the experi- and and the number of problems that have been encountered, it is roadways feasible to continue use of this type of treatment. not SUMMARY were conducted with the No. 8 slurry seal and precoated Experiments 8 chip seal to determine their performance. The major conclusions No. placed; and (2) the use of the No. 8 chip seal is not warranted due be the problems encountered and the cost involved. to 17

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23 Oil, and David Mahone, Ken McGhee, Gene Leake, and Ray Gunn of Central Research Council for their contributions to the conduct of the the and to Harry Craft of the Council for editing the report, evaluation, to Ivy Carlton and Jean Vanderberry for typing. and ACKNOWLEDGEMENTS author expresses thanks to Paul Cecchini and the Staunton The personnel, Fred Dabney of Richmond Pavers, Ed Harnack of District 19

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25 Mahone, David C., "Evaluation of No. 8 Aggregate Seal and i. Virginia Highway and No. 8 Precoated Chip Seal " Route ii, on T ransportation Research Council, May "Average Daily Traffic Volumes on Interstate Arterial and Primary 2. published annually by the Virginia Department of Highways Routes," McGhee, K..H., "Design of Overlays Based on Pavement Condition, 3. and Deflections," Virginia Highway and Transportation Roughness, Vaswani, N. K., "Design Guide for Secondary Road Pavements in 4. Virginia Highway Research Council Report 73-R18, October Virginia," REFERENCES and Transportation. Research Council Report 82-R31, Design Method for Flexible Pavements in "Recommended Virginia Highway Research Council Report 71-R26, March irginia,"

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27 O 8.5O i i0-i0.60 i0. I I i0.90-ii. ii.04-ii H NP I-3 S-5 S H H S APPENDIX A HISTORY OF PAVEMENT BETWEEN MILEPOSTS 6.10 AND Northbound Lanes Milepost Type Placed B B B 1974 B B I-2 NP Lanes Southbound NP B B B

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30 APPENDIX B (continued)

31 APPENDIX B (continued)

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33 Average APPENDIX C CLIMIATOLOGICAL DATA Rainfall, in. Temperat.ur.es, Deg. F: Month High Low Low High High Low January February March April May June July August 48 i. 80 I Ii September October November December Total NOTE: i in cm; 5/9 (Deg. F.- 32) Deg. C.

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35 i i i I i0.87-ii. 22 I0.87-ii ii.22-ii NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL O Seal Old N ry Seal Old Plus No. 8 Plus No. 8 Plus No. 8 Plus No. 8 APPENDIX D SKID DATA Lane Treaded TyPe, Mix Bald Milepost Date S' F Seal Old Old SI== al Precoated S.T. Precoated S.T. S.T. Precoated Precoated S.T. S.T. Conventional Conventional S.T. S.T. Conventional Conventional S.T. B B B B Site Control Control Site Site Control Control Site Precoated S.T. Precoated S.T. S.T. Precoated S.T. Precoated S.T. Conventional Conventional S.T. Convent ional S.T. S.T. Conventional

36 Appendix D i0.87-ii ii ii ii.22-ii.58 ii.22-ii.58 ii.22-ii.58 ii. 22-ii.58 NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL NBTL NBPL SBTL SBPL Plus No. 8 Plus No. 8 Plus No. 8 Plus No. 8 (continued) Bald Treaded Lane Milepost Date Type Mix B B B B Site Control Site Control Control Site Site Control