10-189 (4) Specific Gravity The specific gravity shall be 1.95- 2.20 in accordance with ASTM D792.
5.Softening P oint The softening point shall be 215 ± 15°F in accordance with ASTM D36.
6.Drying Time When applied at a thickness of 125 mils, the material shall set to bear traffic in no more than 2 minutes when air and substrate temperature is 50°F ± 3°F (and no more than 10 minutes when the air and substrate temperature is 90 °F ± 3 °F when applied at temperature of 412.5 ± 12.5°F in accordance with AASHTO T 250.
7.Alkyd/Maleic Binder Determination The thermoplastic material shall immediately dissolve in diacetone alcohol. Slow dissolution is evidence of the presence of hydrocarbon binder components.
8.Indentation Resistance The Shore Type A2 Durometer with a 4.41 lb. load applied shall be between 40 and 75 units after 15 seconds at 115°F in accordance with ASTM D2240. 1087 -8 MATERIAL CERTIFICATION Furnish the following pavement marking material certifications in accordance with Article 106- 3. When tested, the material shall meet the physi cal and chemical characteristics provided by the manufacturer. NCDOT reserves the right to compare these test results to baseline test results gathered by the NCDOT Materials and Test s Unit. If not NCDOT standard glass beads, then must meet AASHTO M 247 Type 3 or 4 and a NCDOT Type 2 Material Certification must be provided. Drop -on Reflective Media Type 3 Material Certification and Type 4 Material Certification Intermix Reflective Media Type 2 Material Certification and Type 3 Material Certification Paint Type 3 Material Certification Removable Tape Type 3 Material Certification Extruded Thermoplastic Type 3 Material Certification and Type 4 Material Certification Heated -In-Place Thermoplastic Type 3 Material Certification Cold Applied Plastic Type 2 Material Certification and Type 3 Material Certification Polyurea Type 2 Material Certification and Type 3 Material Certification 1088 -1 REFLECTIVE UNIT REQUIREMENTS FOR DELINEATORS
A.Definition Refer to ASTM D4956. Define “entrance angle” as the angle at the reflector between direction of light incident on it and direction of reflector axis. Define “observation angle” and “specific intensity” in accordance with Subarticle 1086 - 3(C)(3)(a). 10-190 (B) Reflective Elements
1.Prismatic Plastic Type
a.General Use an acrylic plastic prismatic reflector hermetically sealed to an acrylic plastic back. The reflector shall consist of a clear and transparent face, herein referred to as a lens, with an acrylic plastic back fused to the lens under heat pressure around the entire perimeter of the lens. Where a central mounting hole is required, permanently seal the unit against dust, water and water vapor. The lens shall consist of a smooth front surface free from projections or indentations except a central mounting hole and identification markings. Mold the manufacturer’s trademark l egibly into the face of the lens.
b.Specific Intensity Refer to ASTM D4956. The specific intensity of each prismatic plastic type reflector shall meet Table 1088- 1 measurements made with reflectors spinning. Failure to meet the specific intensity minimum wi ll constitute failure of the lot. TABLE 1088 -1 OPTICAL PROPERTIES OF PRISMATIC PLASTIC TYPE REFLECTORS Observation Angle (Degrees) Entrance Angle (Degrees) Minimum Specific Intensity (Can dlepower per Footcandle) Crystal Yellow Red 0.1° 0° 119 71 0.1° 15° 119 28 -- 0.1° 20° 47 28 0.1° 35° 50 30 -- Locate the prismatic plastic type reflector to be tested at a distance of 100 f eet from a single light source having an effective diameter of 2 inches operate the light source at approximately normal efficiency. Measure the return light from the reflector by a photoelectric photometer having a minimum sensitivity of 1 x 10 footcandles per mm scale division. The photomete r shall have a receiver aperture of 0.5 inch diameter, shielded to eliminate stray light. The distance from light source center to aperture center shall be 2.1 inches for 0.1 degree observation angle. During testing, spin the reflectors to average the or ientation effect. If a test distance other than 100 f eet is used, modify the source and aperture dimensions, and the distance between source and aperture, in the same proportion as the test distance.
c.Durability
i.Seal Test Use the following test to determine if a reflector is adequately sealed against dust and water: Submerge 50 samples in water at room temperature. Subject the submerged samples to a vacuum of 5 inches gauge for 5 minutes. Restore atmospheric pressure and leave the samples submerged for 5 minutes, then examine the samples for water intake. Evidence of any water is a failure. Failure of more than 2% of the number tested will be cause for rejection. 10-191 (ii) Heat Resistance Test Test three reflectors for 4 hours in a circulating air oven at 175°+5°F. Place the test specimens in a horizontal position on a grid or perforated shelf, permitting free air circulation. At the conclusion of the test, remove the samples from the oven and permit them to cool in air to room temperature. The samples, after exposure to heat, shall show no change in shape and general appearance when compared with unexposed control standards. Any failures will be cause for rejection.
2.High Performance Sheeting Grade The reflective sheeting shall be Grade C retroreflective sheeting that conforms to
Article 1092 — 2.
1088 -2 GUARDRAIL AND BARRIER DELINEATORS
A.Brackets and Casings for Delineators Make brackets for guardrail and barrier delineators out of 12 gauge galvanized steel, 0.063 inch thick aluminum alloy, or .080 inch thick polycarbonate. Use molded plastic type guardrail and barrier delineators that consist of a plastic casing and a reflective element.
B.Reflective Element Requirements The refl ective element shall meet Article 1088 -1. In addition, guardrail delineators and side mounted barrier delineators shall have a minimum reflective area of 7 sq.in. Top mounted barrier delineators shall have a minimum reflective area of 28 sq.in.
C.Material Certification Furnish a Type 2 material certification in accordance with Article 106 -3 for all guardrail and barrier (permanent) delineators and a Type 7 material certification for all guardrail and barrier delineators (temporary) before use.
D.Approval All materials are subject to the approval of the Engineer. 1088 -3 GUARDRAIL END DELINEATION
A.General Use guardrail end delineation that is adhesive coated yellow reflective sheeting applied with a pressure sensitive adhesive backing.
B.Reflective Sheeting Requirements Use Grade C yellow retroreflective sheeting which conforms to Article 1092 -2 for all guardrail end delineation. In addition, guardrail end delineation shall have a minimum reflective area of 2 sf for curved end sections or cover the entire portion of squa re end sections. See Roadway Standard Drawings .
C.Material Certification Furnish a Type 2 material certification in accordance with Article 106 -3 for all guardrail end delineation before use.
D.Approval All materials are subject to the approval of the Enginee r. 10-192 1088 -4 OBJECT MARKERS
A.General Use 7 f eet galvanized steel U -shaped channel posts as supports for delineators that are fabricated from steel conforming to ASTM A36 or ASTM A409. Use 7 f eet posts, which weigh at least 1.12 lbs/lf after fabrication and application of protective finish. Punch or drill all posts with 3/8 inch diameter holes on the centerline, spaced on 1 inch centers, starting 1 inch from the top and extending a t least 24 inches down the posts. Make sure that the holes are clean and the posts are free of burrs. Hot dip galvanize the posts after fabrication for the full length and total area in accordance with ASTM A123.
B.Reflectors Use 3 inches diameter prismatic plastic reflectors on object markers that meet Subarticle 1088- 1(B)(1).
C.Reflective Sheeting Requirements Use Grade C retroreflective sheeting on object markers that meet Article 1092 -2.
D.Panel Requirements Use panels that meet Article 1092 -1.
E.Fasteners Use fasteners that meet Article 1092 -1.
F.Material Certification Furnish a Type 5 material certification in accordance with Article 106 -3 for sheeting, a Type 2 material certification for delineators and a Type 1 material certification for U-channel posts bef ore use.
G.Approval All materials are subject to the approval of the Engineer. 1088 -5 TUBULAR MARKERS
A.General Provide tubular markers that are made of ultraviolet stabilized plastic impact resistant material found on the NCDOT APL . Products must be current with the applicable AASHTO Product Evaluation & Audit Solutions workplan to remain on the NCDOT APL. Provide yellow , white or gr ay tubular markers as shown in the plans. Provide tubular markers that are flexible or have a flexible joint at the base, such that it will return to its original shape and position if struck by a 5,000 lb vehicle at a velocity of 55 mph. When struck the tubular markers shall not permanently distort to a degree that would prevent reuse. Use tubular markers that are circular in shape and have a minimum height of 36 inches with a broadened bas e. Use tubular markers that have a minimum height of 42 inches on roadways with posted speed limits greater than 50 mph. Design tubular markers that have white retroreflective collars or as shown in the contract. Where retroreflective collars are require d, provide Grade C retroreflective sheeting or better that meets Article 1092 -2. Use retroreflective sheeting bands with a minimum width of 4 inches with 6 inches between the bands. Apply a continuous strip of sheeting completely around the tubular marke r to ensure 360° retroreflectivity. 10-193 (B) Material Certification Furnish a Type 3 material certification in accordance with Article 106 -3 for all new tubular markers and retroreflective collars and a Type 7 material certification for all used tubular markers and retroreflective collars before use.
C.Approval All materials are subject to the approval of the Engineer. 1088 -6 FLEXIBLE DELINEATOR
A.General Provide flexible delineators found on the NCDOT APL . Products must be current with the applicable AASHTO Product Evaluation & Audit Solutions workplan to remain on the NCDOT APL.
B.Retroreflective Sheeting Use retroreflective sheeting that is a minimum area of 16 sq.in., with a minimum width of 3 inches . The reflective sheeting shall be Grade C retroreflective sheeting or better and shall conform to Article 1092- 2. Use retroreflective sheeting which is yellow, red or white , as shown in the plans. Attach the retroreflective sheeting on the f ront and back of the delineator post as required by the contract.
C.Post Design a delineator post that is flexible and made of recycled material. Provide a delineator post that is resistant to impact, ultraviolet light, ozone, hydrocarbons and stiffening wi th age. Provide a post that is not seriously affected by exhaust fumes, asphalt or road oils, dirt, vegetation, soil, deicing salts or any other types of air contamination or materials likely to be encountered. Upon weathering, the post shall not exhibit serious discoloration, checking or cracking, peeling or blistering, swelling, shrinking or distortion, or any other detrimental effects. Weathering shall not cause appreciable strength or flexibility loss. Design a post with a smooth surface that is free from irregularities or defects. The surface of the post shall not soil excessively. If soiling does occur, it shall be easily cleaned using detergent and water, or solvent. Use posts that have a convex shaped cross -section. The ch ord distance for the cr oss-section 31 shall be from 3.5 inches to 4.5 inches in length. Design a post such that it can maintain straightness throughout its entire life. Straight is defined as no point along its length any more than 1 inch away from a perfectly straight edge placed longitudinally along any side of the post. Provide a post in which both sides of the top of the post accepts, and holds securely, retroreflectorized sheeting. Design posts that are gray in color.
D.Base Support Provide a base support that is hot rolled rail steel or new billet steel meeting
Article 1088 — 5, the physical requirements of ASTM A499 and the chemical requirements
of ASTM A1. Use a base support that is a uniform flanged U -channel post with a nominal we ight of 3 lb./ft. before holes are punched. Use base support posts that are 18 inches in length and
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 605–609 of 857.