【国外标准】 Standard Test Method for No-Pick-Up Time of Pavement Markings

3.1 This test method serves as a laboratory control test. Types of pavement markings that can be tested with this method are waterborne traffic paint, solvent borne traffic paint, and some two component 100 % solids liquid pavement markings, such as epoxy and modified epoxy pavement markings. If wet film thickness, temperature, and humidity are controlled within the tolerances specified herein, this method can be useful for relative testing of pavement markings and potentially for qualification of pavement markings for field application in approved specifications. For improved repeatability and meaningful comparison of pavement markings samples being tested, consistent air flow over the pavement marking films during testing is important. The buyer and seller should agree upon the air flow conditions, whether it be static or carefully regulated air flow (see 4.6.1 and 4.6.2). Because of the many variables operative in the field application of pavement markings (for example, wet film thickness, air temperature, humidity, wind speed, pavement type (asphalt or concrete), film profile over pavement, pavement temperature, pavement porosity, pavement moisture content, and the presence or absence of direct sunlight during striping), a direct correlation between the results of this test and field applications is difficult to obtain. However, relative field performance can be predicted using this method if the testing protocol is adhered to. For testing of two component 100 % solids liquid pavement markings an application of drop on retroreflective optics are typically applied at a specified rate to the markings prior to testing. For these types of pavement markings the regulation of air flow is not necessary due to the drying mechanics of the product.1.1 This test method covers a laboratory procedure for determining the no-pick-up time of pavement markings. The method uses a wheel consisting of a metal cylinder with rubber O-rings. The wheel is rolled down a ramp over a freshly applied pavement marking film repeatedly until there is no transfer of the marking material to the rubber rings. The elapsed time from pavement marking film application to point of no marking material transfer is the no-pick-up time. Key variables to be controlled during testing are wet film thickness, temperature, humidity, air flow, and use of retroreflective optics. This standard provides three options for the testing of the no-pick-up time for pavement markings. The first option, Method A, specifies controls for temperature, humidity, and air flow during testing; a second option, Method B, specifies controls for temperature and humidity during testing, and a third option, Method C, provides guidance for performing this with a drop on application of retroreflective optics such as glass beads, Waterborne and Solvent Borne pavement markings are typically tested using Procedure A or Procedure B, without the application of drop on retroreflective optics. Pavement markings that are two component 100 % solids are typically tested using Method C.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.