Specifications include, but are not limited to: OPTICS: Optics shall be beads or elements incorporated into pavement markings so as to produce reflectorized pavement markings. Optics shall be one of the products listed on the Agency’s Approved Product List for the respective material specification and shall meet the following requirements. 1. Optics, Type I. Optics, Type I shall be standard optics consisting of glass beads free from carbon residue. Optics, Type I shall conform to the requirements of AASHTO M 247, Type 1, except as modified below. a. Roundness: Roundness shall be a minimum of 80% true spheres, as determined in accordance with ASTM D 1155. b. Moisture Resistance: Optics shall be moisture resistant in accordance with AASHTO M 247. c. Chemical Resistance: Optics shall be resistant to hydrochloric acid, water, calcium chloride, and sodium sulfide in accordance with Section 4.3.6 to Section 4.3.9 of Federal Specification TT-B-1325D.
