Guidelines for the Use of Waste Plastic in Hot Bituminous Mixes (Dry Process) in Wearing Courses

IRC SP 98: Introduction - Key Specifications & Tables

1. Plastic Types for Pavement Use

Only thermoplastic waste plastics are used, classified as:

Thermosetting plastics (e.g., Epoxy, Melamine) are not used.

2. Dense Graded Mix Properties (Table 3)

Summary Diagram: Plastic Use in Bituminous Mix

flowchart LR
    A[Waste Plastic Types] --> B[LDPE, HDPE, PP, PET]
    B --> C[Processing & Cleaning]
    C --> D[Mixing with Bitumen]
    D --> E[Dense Graded Bituminous Mix]
    E --> F[Properties as per Table 3]

Use these specifications to ensure quality and durability in waste plastic modified bituminous pavements per IRC SP 98.

IRC SP 98 - Scope Summary

The scope of IRC SP 98 covers the use of waste plastics as modifiers in bituminous pavement layers. Key points include:

• Applicable Waste Plastics: Only LDPE, HDPE, PET, and Polyurethane are permitted.

• Purpose: To enhance pavement durability and performance by incorporating waste plastics into bituminous mixes.

• Mix Design: Focus on dense graded mixes modified with 6-8% waste plastic by weight of bitumen, adjusted for rainfall conditions.

• Performance Requirements:

  Parameter	Value
  Minimum Stability (kN @60℃)	12.0
  Flow (mm)	2 - 4
  Marshall Quotient (kN/mm)	2.5 - 5
  Compaction	75 blows/face
  Air Voids (%)	3 - 5
  Retained Stability (%)	≥ 98
  Indirect Tensile Strength (MPa)	≥ 0.9
  Voids in Mineral Aggregate (VMA)	16
  Voids Filled with Bitumen (VFB)	65 - 75

• Advantages: Improved strength, durability, and environmental benefits by recycling plastic waste.

• Limitations: Specific plastic types only; quality control critical during manufacturing and construction.

flowchart LR
    A[Waste Plastic Types] --> B[LDPE, HDPE, PET, Polyurethane]
    B --> C[Plastic Preparation]
    C --> D[Mixing with Bitumen (6-8% by weight)]
    D --> E[Dense Graded Bituminous Mix]
    E --> F[Pavement Construction]
    F --> G[Enhanced Pavement Performance]

This scope ensures sustainable pavement construction with defined material and performance criteria per IRC SP 98.

Advantages of Using Waste Plastic as Modifier and Binder (IRC SP 98, Clause 3):

• Higher resistance to deformation (improved rutting resistance).
• Enhanced resistance to water-induced damage.
• Increased durability and improved fatigue life.
• Improved stability and strength of bituminous mixes.
• Environmentally friendly by utilizing waste plastic disposal.

Limitations & Specifications:

• Only LDPE, HDPE, PU (limited), and PET plastics are allowed.
• Black colored plastics (from repeated recycling) must NOT be used.
• PVC is prohibited due to toxic dioxin release.
• Thermal degradation and harmful gas evolution occur beyond 180°C; temperature control during mixing is critical.
• Waste plastic size: passes 2.36 mm sieve, retained on 600 micron sieve.
• Impurities (dust etc.) ≤ 1% (measured by ash content at 600°C).
• Melt flow index per ASTM D 1238-2010 must be within specified range (to ensure compatibility).

Summary Table: Waste Plastic Specifications

flowchart LR
    A[Waste Plastic] --> B{Type}
    B -->|LDPE, HDPE, PU, PET| C[Processed Plastic]
    B -->|Black/PVC| D[Rejected]
    C --> E{Size}
    E -->|600 micron < size < 2.36 mm| F[Accepted]
    E -->|Outside range| D
    F --> G{Impurities}
    G -->|≤1%| H[Approved for Mixing]
    G -->|>1%| D
    H --> I[Dry Process: Added to Hot Aggregate]
    H --> J[Wet Process: Added to Hot Bitumen]

Note: Proper temperature control and quality checks are essential to realize benefits and avoid environmental hazards.

IRC SP 98: Key Specifications for Materials

1. Classification of Plastics (Clause 1.4)

• Thermoplastics: Can be reshaped on heating (used in pavement).
• Thermosetting: Once set, cannot be remolded (not used in pavement).

2. Waste Plastics Allowed in Pavement (Clause 1.5)

• Only LDPE, HDPE, PET, Polyurethane conforming plastics are permitted.
• Sources include carry bags, bottle caps, milk pouches, etc.

3. Dense Graded Mix Properties (Clause 5.1 - Table 3)

Summary Diagram: Material Flow for Waste Plastic Pavement

flowchart LR
    A[Waste Plastic Sources] --> B[Sorting & Cleaning]
    B --> C[Shredding & Size Reduction]
    C --> D[Mixing with Bitumen]
    D --> E[Dense Graded Bituminous Mix]
    E --> F[Pavement Construction]

Note: Use only specified thermoplastics and maintain mix properties within the

Design of Mix: Waste Plastic Modified Dense Graded Bituminous Pavement (IRC SP 98, Clause 5.1)

Plastic Types & Melt Flow Index (Clause 9.0):

• LDPE: 0.14 to 58 gm/10 min
• HDPE: 0.02 to 9.0 gm/10 min

Notes:

• Waste plastic content varies with climatic conditions; higher content for high rainfall areas.
• Compaction and air voids are critical for durability and performance.
• Marshall Stability and flow ensure mix strength and flexibility.

flowchart TD
    A[Bitumen] --> B[Add Waste Plastic 6-8%]
    B --> C[Mix with Aggregates]
    C --> D[Compaction: 75 blows each face]
    D --> E[Check Properties: Stability, Flow, Air Voids]
    E --> F[Use in Pavement Layer]

This summarizes the key design parameters and specifications for waste plastic modified bituminous mixes per IRC SP 98.

IRC SP 98: Manufacturing Bituminous Mix Using Waste Plastic (Dry Process)

Key Specifications:

• Waste Plastic Content: 6-8% by weight of bitumen (adjust bitumen quantity accordingly).
• Plastic Types Allowed: LDPE, HDPE, PU (limited), PET.
• Prohibited Plastics: PVC (toxic gases), black recycled plastics.
• Max Temperature: 180°C to avoid thermal degradation and toxic gas evolution.
• Process: Dry process only — shredded plastic added to hot aggregates, not mixed directly with bitumen.

Advantages:

• Doubles binding property of aggregates.
• Increases mix stability and durability.
• Enhances resistance to deformation and water damage.
• Environmentally friendly waste disposal.

Manufacturing Notes:

• Plastic coats the aggregates improving surface properties.
• No new equipment needed.
• Temperature same as normal road laying.

Summary Table:

flowchart TD
    A[Hot Aggregates] --> B[Add Shredded Waste Plastic (6-8% by wt of bitumen)]
    B --> C[Plastic Coats Aggregates]
    C --> D[Mix with Bitumen (Reduced quantity)]
    D --> E[Bituminous Mix with Enhanced Properties]

This ensures improved stability, durability, and environmental benefits as per IRC SP 98 guidelines.

IRC SP 98: Transportation and Storage Key Points

The code does not explicitly provide a dedicated clause for transportation and storage of waste plastic modified bituminous mixes. However, based on typical engineering practice and the context of IRC SP 98 on waste plastic bituminous mixes:

Transportation

• Transport bituminous mixes at temperatures maintaining mix workability (typically 140-160°C).
• Avoid segregation and temperature drop by using insulated trucks or covered containers.
• Minimize transport time to prevent cooling and stiffening of the mix.

Storage

• Storage of bitumen modified with waste plastic should be done in sealed, insulated tanks to maintain temperature and prevent contamination.
• Plastic-modified bitumen should be stored at 150-160°C to maintain homogeneity.
• Avoid prolonged storage to prevent aging or segregation of plastic particles.

Relevant Specifications from IRC SP 98 (Clause 5.1 Table 3):

Waste Plastic Types Allowed (Clause 1.5 & 1.4)

• Thermoplastics only: LDPE, HDPE, PP, PVC (PVC use limited due to thermosetting nature).
• Waste plastic sources: carry bags, bottles, caps, wrappers, etc.

flowchart LR
    A[Plastic Waste Collection] --> B[Sorting & Cleaning]
    B --> C[Shredding & Grinding]
    C --> D[Mixing with Bitumen at 150-160°C]
    D --> E[Transportation (Insulated Trucks)]
    E --> F[

Quality Control & Testing for Waste Plastic Modified Dense Graded Bituminous Mixes (IRC SP 98)

Key Specifications (Table 3):

Material Requirements:

• Waste plastic size: passing 2.36 mm sieve and retained on 600 micron sieve.
• Dust/impurities ≤ 1% (ash content test at 600℃).
• Melt flow index per ASTM D 1238-2010 to ensure compatibility with binder.

Notes:

• Use thermoplastic waste plastics only (e.g., PP, PVC, LDPE, HDPE).
• Thermosetting plastics are not suitable for pavement.

Testing Procedure Summary:

1. Marshall Stability & Flow Test at 60℃.
2. Compaction: 75 blows on each side of specimen.
3. Air Void Measurement using standard volumetric methods.
4. Retained Stability after water conditioning.
5. ITS Test for tensile strength.
6. Plastic Waste Quality: sieve analysis, impurity test, melt flow.

flowchart LR
    A[Waste Plastic] --> B[Size & Purity Check]
    B --> C[Melt Flow Test (ASTM D1238)]
    C --> D[Mixing with Bitumen]
    D --> E[Specimen Preparation]
    E --> F[Marshall Stability & Flow Test]
    E -->

Safety and Environmental Considerations in IRC SP 98: Waste Plastic Modified Bituminous Mixes

• Plastic Types Allowed: Only thermoplastic plastics—LDPE, HDPE, PET, and Polyurethane—are permitted. Thermosetting plastics (Epoxy, Melamine, Polyester) are excluded for pavement use (Clause 1.4 & 1.5).

• Plastic Sources: Waste plastics must originate from common consumer products like carry bags, bottles, caps, pouches, etc. (Table 2).

• Environmental Benefit: Use of waste plastic reduces plastic pollution and landfill load, promoting sustainability.

• Safety in Handling:

  • Use proper PPE during heating (avoid inhalation of fumes).
  • Control temperature to prevent plastic degradation.
  • Ensure proper ventilation at manufacturing sites.

• Mix Specifications (Table 3):

  Parameter	Value
  Waste Plastic Content	6-8% by weight of bitumen
  Minimum Stability	12.0 kN at 60℃
  Flow	2-4 mm
  Marshall Quotient	2.5 - 5 kN/mm
  Air Voids	3-5%
  Retained Stability	≥ 98%
  ITS (Minimum)	0.9 MPa
  VMA	16%
  VFB	65-75%
  Compaction	75 blows each face

flowchart TD
    A[Waste Plastic Collection] --> B[Sorting Thermoplastics Only]
    B --> C[Shredding & Cleaning]
    C --> D[Mixing with Bitumen at Controlled Temp]
    D --> E[Manufacturing Bituminous Mix]
    E --> F[Quality Control & Testing]
    F --> G[Safe Construction Practices]

Summary: IRC SP 98 emphasizes using specific thermoplastic waste plastics, controlled mix design parameters, and safe manufacturing practices to ensure environmental safety and structural performance.

IRC SP 98: Application and Field Performance of Waste Plastic Modified Dense Graded Bituminous Mixes

Key Specifications (Table 3 - Clause 5.1)

Notes:

• Waste Plastic Type: Thermoplastics only (e.g., PP, PVC, LDPE, HDPE) as thermosetting plastics are not suitable.
• Plastic Content: Adjusted based on climatic conditions (higher in high rainfall areas).
• Compaction: Marshall compaction with 75 blows per face ensures proper density and durability.

Summary Formulae:

• Marshall Quotient (MQ):
  [ MQ = \frac{\text{Stability (kN)}}{\text{Flow (mm)}} ]

• Retained Stability (%):
  [ \text{Retained Stability} = \frac{\text{Stability after conditioning}}{\text{Initial Stability}} \times 100 \geq 98% ]

Application:

• Use these parameters to design and evaluate waste plastic modified bituminous mixes.
• Ensure field compaction and quality control per specified blow counts and air voids.
• Adjust plastic content based on local climate for optimum performance.

flowchart LR
    A[Plastic Waste] --> B[Shredding & Processing]
    B --> C[Mixing with Bitumen

IRC SP 98: Committee and Development Process Overview

The development of IRC SP 98 involved a structured committee and approval process:

Committee Composition

• Highways Specifications & Standards Committee (HSS): Includes senior officials from MORTH, CRRI, IIT, and industry experts.
• H-2 Committee: Tasked with drafting guidelines on waste plastic bitumen.
• Key members include:
  • Convenor: A.V. Sinha
  • Co-Convenor: Dr. Sunil Bose
  • Member Secretary: Arun Kumar Sharma
• Members from government, research, and industry sectors ensured comprehensive inputs.

Development Process

1. Draft Preparation: Initial draft by Dr. Sunil Bose (March 2013).
2. Deliberations: Multiple H-2 Committee meetings for review.
3. Approval:
   • H-2 Committee approved draft on 17th June 2013.
   • HSS Committee approved on 19th July 2013.
   • IRC Council approved final guidelines in August 2013.

Key Specifications

• The process ensures consensus from technical experts and stakeholders.
• Regular revisions based on feedback and field experience.
• Strict copyright and reproduction controls.

flowchart TD
    A[Draft Preparation by Dr. Sunil Bose] --> B[H-2 Committee Deliberations]
    B --> C[H-2 Committee Approval (17 June 2013)]
    C --> D[HSS Committee Approval (19 July 2013)]
    D --> E[IRC Council Approval (Aug 2013)]

This committee-driven approach guarantees technical robustness and stakeholder buy-in for IRC SP 98 guidelines.

IRC SP 98 Key Appendices and Specifications Summary

Appendix Highlights

• Appendix-1 & Appendix-2 (Pages 10-11): Contain additional technical data and guidelines related to waste plastic modified bituminous mixes.

Key Tables & Specifications for Waste Plastic Modified Dense Graded Mixes (Clause 5.1, Table 3)

Waste Plastic Types Suitable for Pavement (Clause 1.5, Table 2)

• LDPE: Carry bags, milk pouches, cosmetic bottles.
• HDPE: Bottle caps, household articles.
• PP: Wrappers, bottle caps.
• PVC: Pipes, bottles, electrical fittings (not recommended as thermosetting).

Material Classification (Clause 1.4, Table 1)

• Thermoplastics (used): LDPE, HDPE, PP, PVC (some types).
• Thermosetting (not used): Epoxy, Melamine, Polyester.

Summary Diagram: Waste Plastic Modified Bituminous Mix Design

flowchart TD
    A[Plastic Waste Selection] --> B{Thermoplastic?}
    B -- Yes --> C[LDPE, HDPE, PP]
    B -- No --> D[Discard]
    C --> E[Plastic Processing & Shredding]
    E --> F[Mixing with Bitumen (6-8% by weight)]
    F --> G[