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MATERIALS & RESEARCH ~e are y: t ~ at Patterson Transportation Researcher February 23, 2006 INITIAL REPORT u REFERENCES: WP 2004-R-1 OVERVIEW EVALUATION OF CROWN TECHNOLOGY'S TUFFLINE HYDROCARBON THERMOPLASTIC Since 1991, thermoplastic pavement markings have been the primary traffic markings used on resurfacing projects in Vermont. Marking materials that have been applied have consisted of both alkyd and hydrocarbon formulations and have been supplied by a number of manufacturers. However, marketplace consolidation has resulted in limited choices for these materials on construction projects. In an attempt to expand options for pavement markings on projects managed by VTrans, a proprietary hydrocarbon thermoplastic marking was installed on one resurfacing project in 2004 to affirm its effectiveness prior to approval. PRODUCT DESCRIPTION: Tuffline hydrocarbon thennoplastic, manufactured by Crown Technology, LLC of Woodbury, GA. was applied as edge and centerlines on US 7 as part of the St. Albans- Swanton ST 2335(1)S project. The product literature states that this material can be applied to both asphalt and PCC pavements using conventional screed extrusion, ribbon extrusion or spray equipment. It can also be used over existing alkyd and hydrocarbon thermoplastic. APPLICATION The yellow center line was applied on August 6 1 h 2004 while the white lines were applied on August h Both days were sunny with temperatures ranging between 70 to 85 degrees. No problems were noted during the application by the project engineer. The markings were applied using the screed extrusion method on the northerly miles of the project from MM 1.53 to MM in Swanton. The remainder of the project from MM in St. Albans to MM 1.53 in Swanton was marked with Stud-Guard SG 70 manufactured by Ennis Paint of Ennis, Texas. RETROREFLECTIVITY There are four test sites placed randomly along the project in the experimental markings. Each test site contains five test areas marked out at 10 feet intervals on both the Northbound and Page 1 of7 Southbound white edge lines as well as both the Northbound and Southbound yellow center lines. Test sites 1, 2, and 3 are the experimental Tufflinc hydrocarbon by Crown Technology, LLC. Test site 4 is the control, Thermoplastic, Stud-Guard SG 70 by Ennis Paint. Initial retroreflectivity was sampled on October 7, 2004, with readings taken on this day averaging 368 mcdl for the Tuffline and 455 mcdl for the SG 70 white lines. The readings on the yellow lines averaged 152 mcdl for the Tuffline and 179 mcdl for the SG 70 (see Appendix A & B). The durability rating on a scale fi om 1 to 10 was 10 for both the white and yellow lines. The durability rating is gathered according to ASTM D713-90, Standard Practice for Conducting Road Service Tests on Fluid Traffic Marking Materials along with ASTM D913, Standard Method for Evaluating the Degree of Resistance to Wear of Traffic Paint. Figure 1 Test site 3 - Oct. 7, 2004 Figure 2 Test site 2- March 14, 2005 (Cleaning of lines evident) After five months of service, a second set of readings were taken on March 14, Winter cleaning protocol (see Appendix C) was carried out to insure that the lines were clear of salt and dirt from snow removal and salting operations. This can be seen in Figure 2 above. The readings collected at this time on the white edge lines averaged 127 mcdl on the Tuffline markings and 135 mcdl for the SG 70 markings. All data sampled can be seen in Appendix A. The yellow lines were not sampled at this time. A third set of readings was taken on May 12,2005. No readings were recorded for the Southbound white edge lines at test site 1 as a maintenance work crew had the section of road closed for a work event. Numerous attempts to sample the readings at test site 1 were made but access to the test site was not possible. The white edge line readings sampled in May were similar to those taken in March. The average readings collected at this time were 115 mcdl for the Tuffline markings and 160 mcdl for the SG 70 markings. The average readings collected on the yellow center lines were 81 mcdl for Tuffline and 77 mcdl for SG 70. Durability ratings for both March and May were 7 which are in the good range. (See Appendix A & B). In Figure 3 below, some damage can be seen on part of the white line. This pattern of damage seems to indicate chipping due to snowplow contact rather than abrasion due to wear. The most recent set of readings was taken on August 23, These readings were slightly higher than the May 12, 2005 readings with average white edge line readings of 150 mcdl for Tuffline and 168 mcdl for SG 70. Yellow readings averaged 108 mcdl for Tuffline and 95 mcdl Page 2 of7 for SG 70. (Appendix A & B). Durability ratings fell to an average of 6 which remains in the fair to good range.. Figure 3 Test site 3-May 12, 2005 Figure 4 Test site 1 -August 23, 2005 It has been shown through previous research that retroreflectivity readings typically decrease from application into the winter maintenance season, yet rebound in the spring or summer ofthe next year as the road is cleaned. The tables below show this pattern with the increase in the retroreflectivity values for May to August. This compares favorably with roads with similar traffic volumes surveyed in previous studies. The average white edge line readings for both the Tuffline and SG 70 thermoplastic were above the FHW A recommendation of 100 mcdl. Both materials were also above the FHW A recommended value of 80 mcdl for yellow lines which is within serviceable limits. US 7 White Lines Crown Technology's Tuffline (Experimental) 10/07/ /12/ /23/2005 SB NB SB NB SB NB TS n/a TS TS Stud-Guard SG 70 (Control TS Table 1 - Average Retroreflectivity Readings at each Test Site, mcdl US7 Yellow Lines Crown Technology's Tuffline (Experimental) 10/07/ /12/ /03/2005 SB NB SB NB SB NB TS TS TS Stud-Guard SG 70 (Control) TS Table 2- Average Retroreflectivity Readings at each Test Site, mcdl Page 3 of7 SUMMARY After one winter the condition of the pavement markings showed some damage and loss of durability. No cracking or curling on the edges of the lines has been observed at any location along the test site areas. By August 2005, the average retrore.flectivity values for the Tuffline white edge lines markings had reached 150 mcdl for the northbound (NB) lane and 154 mcdl for the southbound (SB) lane. In contrast, the test site with SG 70 (TS 4) averaged 167 mcdl in the NB lane and 169 mcdl in the SB lane. Those area~ marked with Tuffline compared Closely to those areas marked by the SG 70 material with no significant differences in retroreflectivity. While there was a large decrease from the initial retroreflectivity readings, it must be noted that this trend is similar for most pavement marking systems tested by VTrans. At this time, the average retroreflectivity readings were above the values recommended by FHW A. The percentage of tot~ readings below the recommended FHW A values can be seen in Appendix A &B. FOLLOWUP Tuffline thermoplastic is being added to the 2006 Approved Product list with the requirement that a Type A certification is completed when it is used on any 2006 construction projects. Further evaluations will be taken to determine the effectiveness of the pavement markings. A full retroreflective summary is attached. DISCLAIMER The information contained in this report was compiled for the use of the Vermont Agency of Transportation. Conclusions and recommendations contained herein are based upon the research data obtained and the expertise of the researchers, and are not necessarily to be construed as Agency policy. This report does not constitute a standard, specification, or regulation. The Vermont Agency of Transportation assumes no liability for its contents or the use thereof. Page 4 of7 APPENDIX A- RETROREFLECTIVITY VALUES- US 7, ST ALBANS/SWANTON WHITE EDGE LINES 10/7/ North Bound 3/14/05 5/12/05 8/23/ South Bound 10/7/04 3/14/05 5/12/05 * TS no data Tuffline no data no data no data no data TS Tuffline TS Tuffline TS SG /23/ Ave. Median Std. Dev. j% below * * Note that no readings were taken on the South Bound white lines at TS 1 on 5/12/05. Page 5 of7 APPENDIX B- RETROREFLECTIVITY VALVES- US 7, ST ALBANS/SWANTON YELLOW CENTER LINES North Bound South Bound 10/7/04 3/14/05 5/12/05 8/23/05 10/7/04 3/14/05 5/12/05 8/23/05 * * 149 no data TS no data It Tuffline 135 T$ Tuffline TS Tuffline TS SG II It no data no data Ave Median Std. Dev I~~ below 0 * * *Note that no readings were taken on the yellow lines on 3/14/05 Page 6 of7 APPENDIX C- PROTOCOL FOR THE CLEANING OF LINE STRIPPING FOR RETROREFLECTIVE READINGS Equipment needed: 1. Windshield washer fluid 2. Water 3. Two liquid dispensers 4. Towels or rags 5. Squeeze mop and/or sponges 6. Gas powered leaf blower PROCEDURE Step 1 -Mix Y2 water and Yz windshield washer fluid into the first liquid dispenser. The other liquid dispenser should have water only. Step 2 -Thoroughly clean the lines with the windshield washer fluid mixture using the dispenser to spray away as much salt, dirt and other debris as possible. Step 3 - Thoroughly clean the lines with the water dispenser, spraying away the windshield washer mixture. * Note: Make sure you start at the highest point of the surface to be cleaned and wash down to the lowest point. Step 4 - Using the squeeze mop and sponges clean away as much excess water as possible. Wipe the line surfaces with a towel or rag to get the surfaces as dry as possible. Step 5 - Utilizing a gas powered leaf blower or similar device blow the lines off until completely dry. Step 6 - Begin Reflectometer Testing. Page 7 of7
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