Methodology for Thermoplastic Road Marking Paint (MORTH Clause 803)

1. Scope

The work shall consist of providing and laying of pavement marking with hot applied thermoplastic paints (type-2) as per Clause 803 of MORTH specifications and IRC:35.

2. Materials

Materials of road marking shall be hot applied thermoplastic compound meeting requirements of Clause 803.4 of MORTH specifications. Composition, properties, storage life and container marking are summarised below.

2.1 Composition (Table 800-9)

2.2 Key Material Properties

• Luminance: White ≥ 65% (daylight), Yellow ≥ 45%.
• Drying time: Traffic-worthy in ≤ 15 minutes.
• Skid resistance: ≥ 45 (BS 6044).
• Softening point: 102.5°C ± 9.5°C (ASTM D36).
• Storage life: 1 year; must melt uniformly without skins.
• Reflectorisation: Achieved by incorporation of beads (Type-1 premix, Type-2 drop-on).

3. Reflective Glass Beads (Type-1 & Type-2)

Beads must be transparent, colourless, free from defects and meet gradation, roundness and refractive index requirements.

3.1 Gradation (Table 800-10)

Other requirements: Roundness ≥ 70% true spheres; Refractive index ≥ 1.50; Free-flowing.

4. Traffic Arrangement & Control

1. Prepare and get approval of traffic diversion plan from AE (MORTH Clause 112 & IRC SP:55).
2. Provide temporary signboards, barricades, flags, lights and flagmen as approved.
3. Install regulatory/warning signs on both sides of working area.

5. Equipment

Typical plant & equipment:

• Pre-melter & Pram-applicator
• Mechanical broom & Air compressor
• Truck, water tanker
• Survey kit & Infra-red (laser) thermometer

6. Work Methodology

6.1 Preparation

Clean surface thoroughly (broom & air compressor). Remove dust, grease, oil and moisture.

6.2 Pre-Marking

Mark reference centre-line (chalk/rope) to guide applicator and ensure alignment.

6.3 Melting & Heating

Melt material in pre-melter with mechanical stirrer. Maintain temperature per manufacturer's instructions (typ. 180°C ± 10°C). Do not exceed maximum safe heating temperature. Use molten material within recommended period (do not keep molten for more than 4 hours for sensitive binders).

6.4 Application

• Transfer molten material to applicator and maintain application temperature.
• Apply lane markings with screed-box; thickness ≥ 2.5 mm.
• Apply continuous or intermittent lines; use stencils for arrows/letters; hand-spray where required.

6.5 Drop-on Glass Beads

Dispense Type-2 beads using forced-feed bead dispenser while the material is hot. Typical application rate: 250 g/m². Ensure uniform mono-layer coverage before thermoplastic cools.

6.6 Weather & Surface Conditions

Markings shall be applied on dry surfaces with pavement temperature ≥ 10°C.

7. Properties of Finished Road Marking

• Shall not lift in freezing weather.
• No appreciable deformation or discoloration under traffic and road temperatures up to 60°C.
• Resistant to sodium chloride and oil drippings.
• Maintain original dimensions, ductility and position without cracking or chopping.

8. Notes & References

Follow relevant clauses of MORTH (Clause 803, Table 800-9, Table 800-10) and IRC:35 for detailed test methods and sampling. Contractor to provide MTCs and manufacturer certificates for materials.