1.General. Use acrylic emulsion polymer or modified acrylic polymer in the manufacture of the water - based pavement marking paint. Provide paint capable of receiving and holding glass beads for producing retroreflective pavement marking. Provide paint that is free of heavy metals as defined by the EPA. Provide finished paint that is: • Fast-drying; • Capable of withstanding air and roa dway temperatures without: o Bleeding; o Staining; o Discoloring; or o Deforming; • Smooth; • Free of: o Coarse particles; o Skins; or o Any other deleterious materials that are detrimental to its use or appearance; • Homogeneous; and • Will not have detrimental interactions with common roadway chemicals. Provide paint film that is capable of maintaining the original dimensions and placement during the curing period without: • Chipping; • Spalling; or • Cracking.
2.Physical Properties
a.General Provide paint with the physical properties specified in Table 880-01. 460 Table 880 -01 Characteristic Requirement Test Volatile Organic Compounds 1.25 lbs/gal Max ASTM D 3960 Viscosity 83-98 Krebs units ASTM D 562 Grind 3 Hegman Units Minimum ASTM D 1210 No-Pick-Up Time 10 Minutes Max ASTM D 711
b.Dry Through Time. Provide paint with a maximum dry through time of 150 minutes. Dry through is when a twisting thumb action, without pressure, does not distort the paint film. Apply the paint to a non-absorbent substrate at a wet film thickness of 15 mils, with a tolerance of 1 mil. Place the substrate, with the film applied, in a humidity chamber controlled at 90 percent relative humidity with a tolerance of 5 percent and at 72.5°F with a tolerance of 2.5°F.
c.Water Resistance. Prepare a 15 mil wet film thickness sampl e on a non-absorbent substrate; allow to dry at 25°C ±1 for 72 hours. Immerse the sample in distilled water without circulation at 25°C ±1. After 18 hours, remove the sample and allow the panels to dry for two hours. Examine the sample for paint softeni ng, blistering, wrinkling, and loss of adhesion.
d.Freeze-Thaw Stability. Place 1 pint of paint in chamber maintained at -10±1°C for 16 hours. Remove the paint from the chamber and place in ambient conditions (25±1°C) for eight hours. Repeat for a total of five cycles. Acceptable paint shall show no coagulation and no change in viscosity greater than 5 Krebs Units after completion of the freeze thaw cycles.
e.Color. Provide paint with pigment that falls within CIE Chromaticity coordinate limits specified in Table 880 -02. Make color determinations for liquid marking material over the black portion of a 2A or 5C Leneta Chart or equal a minimum of 24 hours after application of a 15-mil wet film. Determine color readings in accordance with the requir ements of ASTM E 1349 using CIE 1931 2-degree standard observer and CIE standard illuminant D65. Table 880 -02 Color 1 2 3 4 x y x y x y x y White 0.355 0.355 0.305 0.305 0.285 0.325 0.335 0.375 Yellow 0.560 0.440 0.490 0.510 0.420 0.440 0.460 0.400
f.Contrast Ratio. Provide paint that when tested according to ASTM D 2805 has a minimum contrast ratio (hiding power) that is 0.96 when drawn down with a 0.005 bird film applicator on a 2A or 5C Leneta Chart and air -dried for 24 hours. Calculate the contrast ratio as black/white. 461 g. Reflectance. Determine the daylight directional reflectance of paint according to ASTM E 1349. Apply a 15- mil wet film to a 2A or 5C Leneta Chart and allow the paint to air dry for 24 hours. Provide white paint with a minimum of 84 percent reflectance and yellow paint with a minimum of 50 percent reflectance.
h.Durability. Provide paint with a minimum durability rating of 7 on both concrete and asphalt pavement, when tested in the skip line area of a Northern NTPEP Test Deck.
i.Retroreflectivity. The minimum retroreflectivity of beaded lines, on both concrete and asphalt pavement, after 12 months of exposure on a Northern NTPEP Test Deck shall be 75 milicandelas per foot candle per square foot, when measured in the skip line area according to ASTM E 1710.