High Performance Thermoplastic Observations in the USA by Potters Asia Pacific
Thermo as we know it o o o o o o o Developed 60 years ago Design largely based on British Standard Traditionally 20% intermixed beads Heat to 200ºC to apply Applied thick; designed to erode. Exposes new beads and white surface Claimed service life of 3 years
Thermo performance o Surface beads erode over first 6 months o Most of performance life relies on intermixed beads o Marking sometimes struggle to hold at 100mcd/lux/m²
Retroreflectivity mcd/lux/m2 Retroreflectivity 350 Japanese field trial by Industry - 1984. 300 Miorolux 12 250 200 30% intermix 150 30% intermix & drop-on 100 20% intermix 50 0 20% intermix & drop-on 3 6 9 12 15 18 21 24 27 30 33 36 39 42 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 traffickin (m onths)
Conventional transverse testing Traffic for 3 million vehicle passes. Measure in the wheel paths, initially, periodically and at the 3m mark.
Retroreflectivity mcd/lux/m2 Australian Road Agency Field Trial - 2008 300 Transverse marking durability trial - >2mm Thermoplastic 250 200 Test four batches of thermoplastic as transverse marking, manufactured to the Australian Standard 150 100 50 0 80,000 vehicles 2.1m vehicles 4.2m vehicles 7 days 6 months 12 months Period of trafficking, with 11,500 lane vehicles / day, 12% heavy vehicles
Thermoplastic cross section Intermixed beads Five years ago we experimented with different intermixed bead mixes
Demonstrates erosion of Thermo One week 29 months Potters Trial AU017, Section 19. Initial measures, dry retro 123mcd, wet retro 40mcd, skid resistance 44BPN. Potters Trial AU017, Section 19. Measures at 29 months, dry retro 182mcd, Wet retro 65mcd, skid 54 BPN.
Results Not fantastic But better Measures aligned with macro pics We discovered it could work better
Investigate US FDOT Spec o THERMOPLASTIC COMPOSITION Binder 20% min o TiO2 Type II Rutile 10% o Glass beads 40% min. 50% Type 1, 50% Type 3 o Calcium carbonate -200mesh 30% max.
FDOT Spec o 3mm thick thermo APPLICATION Thinner film applications of 1.5mm are use in the Spec for refurbishing purposes only. They require 1mm beads (Visibeads) to be surface applied and ask for 300mcd initial and above 150mcd after 1 year of service. Binder concentration is specified at 25%. o Double drop of surface beads. 50:50 large Type D and small Type B.
FDOT Spec PERFORMANCE REQUIREMENTS Retroreflectivity: o The white and yellow pavement markings shall attain an initial retroreflectance of not less than 450 mcd/lx m2 and not less than 350 mcd/lx m2 respectively. o The retroreflectance of the white and yellow pavement markings at the end of the three year service life shall not be less than 150 mcd/lx m2.
Compare Thermoplastic Spec Binder 18% 20% Ti02 No mention Type II Rutile 10% Glass beads 20% intermix 20% large sized beads, plus 20% small sized beads Skid resistance Initial 40BPN No mention After 3m 45BPN Reflectivity Initial 200mcd Initial 450mcd After 3m 100mcd After 3 years 150mcd AS4049 Pt 2 FDOT 971-5.2
filler shall be well dispersed in the resin. The material shall be free from all skins, dirt and foreign objects. US Thermo applicator
We investigated I went to see for myself. Someone had to do it. Potters tech services rep from Texas and the Florida Contract supervisor provided a guided tour.
New marking to FDOT Spec Est ADT 20,000. Open grade AC pavement (SMA). Edgeline observations: Dry retro 620mcd. Wet retro 320mcd.
Nine month old marking Applied March 2008. Est ADT 20,000. Concrete pavement. Lane line observations: Some pop-out of small surface applied beads. Dry retro 780mcd, wet 139mcd.
2 ½ year old marking Applied Spring 2006. Est ADT 50,000. Dense grade asphalt pavement. Edgeline observations: Almost 100% loss of the smaller sized beads. Dry retro 440mcd, wet retro 107mcd.
2 ½ year old marking Applied Spring 2006. Est ADT 200,000 (20 million so far). Dense grade asphalt pavement. Interstate Hwy. Could only measure edgeline at busy merge. Egdeline observations: dry retro 320mcd, wet retro 120mcd. This edgeline carried a lot of traffic.
Florida DOT Spec 971-5 Thermoplastic Materials for Traffic Stripes.
Potters Asia Pacific Conducting R&D with customers, as the demand for safer markings spreads. Always measure the surrounding results In the past 2 years the results have been in a consistent range.
Recent Experience in Asia 600 500 400 300 200 100 0 Taiwan Random Measures of Thermoplastic Retroreflectivity Singapore Malaysia Thailand Indonesia
AUSTRALIA RTA introduces Spec R145 Parameter Initial At one year Intervention level Dry retroreflectivity >250mcd/lux/m² >200mcd/lux/m² >150mcd/lux/m² Wet retroreflectivity >80 mcd/lux/m² >80 mcd/lux/m² >80 mcd/lux/m² Skid Resistance >40BPN >40BPN >40BPN RTA flags all performance requirement to be increased, including the dry intervention level to be increased to 180 by 2011-12, with wet retro and skid resistance also anticipated to be raised.
Recent Sydney Experiences The first contract to fall under this new Spec is North Sydney. Most longitudinal markings in Sydney have been traditionally applied with Thermo. How have the contractors handled this?
Recent Sydney Experiences Many have wasted time and energy in rejecting change, instead of trying to improve their performance. One Alliance group has been working quietly together over the past few years to improve their performance.
Recent Sydney Experiences Crystalite Design - (Sydney manufacturer of high performance thermoplastic.) Guidance Road Management (Sydney Pavement marking contract - applicators of high performance thermoplastic) Working on EDI Downer (NZ) North Sydney Performance contract to Spec R145
Recent Sydney Experiences High performance thermo, with a surface application of Type D-HR antiskid glass bead mix. Field report results by independent RTA Surveillance inspector. These measure have been taken on the busy Sydney Warringah Freeway, almost two months after they were applied. ADT approx 250,000
Some no-brainers How long will Downer EDI need to wait until they need to remark their roads? Will they be making money? Will the RTA be happy with their performance?
I rest my case
Safer thermoplastic pavement marking systems have been trialled and tested and are available and affordable now.