Guidelines for the use of Construction and Demolition Waste in the Road Sector

IRC:121 Introduction - Key Specifications & Typical Properties of Processed C&D Waste

Scope & Advantages

• Guidelines for using processed Construction & Demolition (C&D) waste in road construction.
• Benefits: Resource conservation, cost reduction.
• Limitations: Variability in waste properties, processing requirements.

Typical Properties of Processed C&D Waste (Tables Extract)

Comparison: RCA vs Natural Aggregates

Important Notes:

• Use 40° as conservative friction angle for design.
• RCA shows slightly inferior mechanical properties than natural aggregates but is suitable with proper processing.
• Quality control and processing

IRC 121 - Clause 1.1 Terminology: Key Definitions

• Construction and Demolition (C&D) Waste: Waste from construction, demolition, or renovation of structures (residential, commercial, infrastructure). It includes mixed debris but must be separated from earth, wood, plastic, metals before processing.

• Processed C&D Waste / Recycled Aggregates (RA): Material obtained by crushing and sieving C&D waste to a specified gradation, containing stone aggregates, brickbats, tile pieces, mortar fragments. It meets size and quality specifications for reuse.

• Recycled Concrete Aggregates (RCA): Crushed, size-graded concrete from demolished concrete structures, mainly stone aggregates with some adhered cement mortar, free from brick, tile, or glass.

Important Notes:

• Proper processing (crushing + sieving) is essential to achieve gradation and remove contaminants.
• Separation of non-aggregates (wood, plastic, metal) is mandatory before processing.
• These definitions guide the use of C&D waste in road construction, ensuring quality and environmental compliance.

Summary Table of Terminology

If you need gradation limits or quality specifications, refer to Clauses 7.1 to 7.7 of IRC 121.

flowchart LR
    A[C&D Waste] --> B[Separation]
    B --> C[Remove wood, plastic, metal]
    C --> D[Crushing & Sieving]
    D --> E[Processed C&D Waste (RA)]
    D --> F[Recycled Concrete Aggregate (RCA)]

This diagram shows the processing flow from raw C&D waste to usable recycled aggregates.

IRC 121 – Key Points on C&D Waste Disposal and Utilisation (Clause 1.2)

• Global Practices:

  • Countries like Germany, Japan, USA, UK, France have established recycling systems.
  • Germany’s Closed Loop Recycling includes:
    • Avoiding waste generation
    • Recycling for reuse
    • Minimizing disposal
    • Avoiding recyclable waste disposal
  • Japan achieves ~95% recycling with quality classes:
    • Class H (High), M (Medium), L (Low) quality recycled aggregates.

• Indian Scenario:

  • Delhi generates approx. 3000 TPD of C&D waste.
  • Municipal Corporations handle transport and disposal but with limited processing and space constraints.
  • Studies by CRRI, MCD, Haryana PWD, KRRDA, IEISL show processed C&D waste is suitable for road works.

• Typical Uses in Roads:

  • Embankment fill
  • Granular sub-base and base courses
  • Cement stabilized layers
  • Concrete pavements and kerb stones (using RCA)

Typical Properties of Processed C&D Waste (Summary)

General Formula for Recycling Rate (%)

[ \text{Recycling Rate} = \frac{\text{Quantity of Recycled C&D Waste}}{\text{Total C&D Waste Generated}} \times 100 ]

Summary Diagram: C&D Waste Management Loop

flowchart LR
    A[Construction & Demolition Waste Generation] --> B[Avoid Waste Generation]
    B --> C[Collection & Segregation]
    C --> D[Processing & Recycling]
    D --> E[Reuse in Road Construction]
    E --> F[Reduced Disposal to Landfills]
    F --> B

References:

• CRRI Feasibility Study on C&D Waste in Roads
• IRC 121 Clauses

Key Points on Sources & Properties of C&D Waste Material (IRC 121)

1. Sources of C&D Waste (Clause 1.3)

• Generated mainly from building construction, renovation, and demolition sites.
• Includes waste from concrete, bricks, mortar, plaster, wood, metals, and other debris.

2. Engineering Properties of Processed C&D Waste

3. Properties of C&D Waste Powder (<6.3 mm)

Summary

• C&D waste mainly originates from demolition and construction activities.
• Processed C&D waste aggregates have moderate strength and durability.
• Fine C&D powder exhibits good compaction and shear strength, suitable for sub-base applications.

flowchart LR
    A[Construction & Demolition Sites] --> B[Generation of C&D Waste]
    B --> C[Sorting & Processing]
    C --> D[Coarse Aggregates (>6.3 mm)]
    C --> E[Fine Powder (<6.3 mm)]
    D --> F[Used as Aggregate Replacement]
    E --> G[Used in Sub-base/Filling]

This data aids in reuse and recycling of C&D

Scope of Guidelines - IRC 121 (Summary)

These guidelines cover processed Construction & Demolition (C&D) waste use in road works including:

• Embankment, sub-base, and base course construction
• Manufacturing kerb stones, paving blocks
• Partial replacement of aggregates in cement concrete pavements (PQC, DLC, RCCP, etc.)

Key Restrictions:

• Not for reinforced soil walls or structural/load-bearing concrete (bridges, culverts, flyovers)
• Not for pre-stressed concrete
• Not for bituminous pavement layers
• Use of reclaimed bituminous materials is covered under MORTH Section 519

Important Specifications & Notes

Typical Formula for RCA Usage in Concrete (per international practice)

[ \text{Max RCA %} = \text{Function of desired concrete strength and exposure conditions} ]

Summary Mermaid Diagram

flowchart TD
    A[C&D Waste Processing] --> B[Processed RA & RCA]
    B --> C{Usage in Road Sector}
    C --> D[Embankment, Sub-base, Base]
    C --> E[Kerb stones, Paving Blocks

Advantages and Limitations of Using Processed C&D Waste Products in Road Sector (IRC 121)

Advantages:

• Resource Conservation: Mitigates shortage of natural aggregates and sand.
• Cost Efficiency: Usually available near construction sites, reducing transportation costs.
• Environmental Benefit: Saves landfill space by recycling waste.
• Sustainability: Conserves natural resources (river sand, stone aggregates).

Limitations:

• Variable Strength: Strength characteristics differ from natural aggregates; requires careful quality control.
• Restricted Use: Not recommended for reinforced soil walls, structural concrete (bridges, flyovers), pre-stressed concrete, or bituminous layers.

Key Specifications from IRC 121:

Typical Properties of Processed C&D Waste

International Maximum Substitution in Concrete (Summary from Table 1)

Summary Diagram: Use of

Typical Properties of Processed C&D Waste (IRC 121)

1. Properties of C&D Waste Aggregate (>6.3 mm size) [Table 4]

2. Properties of C&D Waste Powder (<6.3 mm size) [Table 5]

3. Comparison of RCA vs Natural Aggregates [Table 6]

• RCA has higher water absorption (up to 6.9%) and lower specific gravity (~2.17-2.45) than natural aggregates (~2.63).
• RCA exhibits higher ACV and AIV, indicating lower strength.

Design Notes:

• Use φ = 40° as a conservative friction angle for C&D waste in design.
• Consider higher water absorption in mix design.
• C&D waste is suitable for embankment and sub-base layers (Clause 7.2).

Summary Diagram of Properties

graph TD
A[C&D Waste Aggregate (>6.3 mm)] --> B[Specific Gravity: ~2.17-2.45]
A --> C[ACV: 35-37%]
A --> D[AIV: 31-35%]
A --> E[

Effect of C&D Waste Usage in Cement Concrete (IRC 121 - Clause 9.66)

Key Points:

• Recycled Concrete Aggregate (RCA) contains adhered hardened cement paste → lower specific gravity, higher porosity, and water absorption.
• This leads to weaker Interfacial Transition Zone (ITZ) and reduced concrete strength.
• Workability (slump) decreases with increasing RCA content.

Table: Strength Variation with RCA Replacement in High Strength Concrete (Cement 500 kg/m³, w/b = 0.243)

Observations:

• Compressive strength reduces ~25% at 100% RCA replacement.
• Up to 20% RCA replacement gives comparable strength to natural aggregates.
• Drying shrinkage and creep may increase but remain within permissible limits.
• RCA concrete shows increased permeability → higher chloride ingress risk.
• Better carbonation resistance but lower abrasion resistance.

Typical Properties of Processed C&D Waste Aggregates (Table 4):

• Specific Gravity: 2.30 (coarse), 2.67 (fine)
• Water Absorption: ~4.5% (coarse), 13-14.8% (fine)
• Aggregate Crushing Value: 37%
• Soundness (Na2SO4): 1.6%

International Limits (Table 1, Clause 37.5):

• UK: RCA max 20

Key Specifications & Properties for C&D Waste Processing Plant (Delhi) - IRC 121

1. Engineering Properties of Processed C&D Waste Aggregates (6.3-20 mm)

2. Properties of C&D Waste Powder (<6.3 mm)

3. C&D Waste Processing Plant (Burari, Delhi)

• Capacity: Expanded from 500 TPD to 2000 TPD.
• Processes: Manual & mechanical segregation, crushing (200-400 mm), dry & wet processing.
• Wet processing includes Grizzly crushers, Vibro screens, Evo-wash, sedimentation tanks.
• Water recycling reduces fresh water usage to 10-15%.
• Products: Coarse aggregates, manufactured sand, paver blocks, kerb stones.
• Market price is 10-20% lower than Delhi Schedule of Rates (DSR).

4. Concrete Mixes with RCA (Table 16)

IRC:121 - Specifications & Methodology for Using Processed C&D Waste in Road Sector

Key Specifications (Clause 7)

• 7.1 Processing of C&D Waste

  • Crushing, screening, and removal of impurities to achieve suitable gradation and quality.

• 7.2 Embankment Construction

  • Use processed C&D waste with controlled moisture content and compaction to achieve required density.

• 7.3 Granular Sub-base (GSB) using Recycled Concrete Aggregate (RCA)

  • Gradation as per IRC: 37 or IRC: 44 standards.
  • Minimum CBR: 30% recommended.

• 7.4 Use of Recycled Aggregate (RA) in GSB Layer

  • RA must be free from deleterious materials; grading must comply with GSB specifications.

• 7.5 Cement Stabilized Sub-base/Base Course

  • C&D waste blended with OPC, typical cement content: 3-5%.
  • Compressive strength: Minimum 1.5 MPa at 7 days.

• 7.6 Granular Base Course

  • Use well-graded C&D waste with adequate strength and durability.

• 7.7 Use in Cement Concrete Pavement & Paving Blocks

  • RCA can replace natural coarse aggregate up to 30%.
  • Ensure water absorption < 5%, Los Angeles Abrasion < 40%.

Typical Properties of Processed C&D Waste

Quality Management

• Regular testing for gradation, strength, and impurities.
• Compliance with IRC standards for each pavement layer.

flowchart TD
    A[C&D Waste Collection] --> B[Processing Plant]
    B --> C[Crushing & Screening]
    C --> D[Quality Testing]
    D --> E{Suitable for Use?}
    E -- Yes --> F[Use in Road Layers]
    E -- No --> G[Reprocessing or Disposal]

Summary: IRC

IRC 121: Processing of C&D Waste - Key Specifications and Properties

1. Processing of C&D Waste (Clause 7.1 & 7.2)

• C&D waste is processed by crushing and screening to produce aggregates for embankment construction.
• Size classification:
  • Coarse aggregates: > 6.3 mm
  • Fine aggregates (powder): < 6.3 mm

2. Typical Properties of Processed C&D Waste Aggregates (Clause 6.3, Table 4)

3. Properties of C&D Waste Powder (< 6.3 mm) - Table 5

Summary Notes:

• High bearing capacity (CBR 74%) makes processed C&D waste suitable for embankment fill.
• Low soundness value (1.6%) indicates good durability.
• Non-plastic nature ensures minimal

Key Specifications & Properties for Processed C&D Waste in Embankment Construction (IRC 121)

1. Particle Size Limits:

• Earth embankments: Max particle size ≤ 75 mm (crushed).
• Rockfill embankments: Max particle size ≤ 300 mm (subject to field compaction demonstration).

2. Side Slope Protection (Good Earth Cover):

Embankments ≥ 6 m require stability design as per IRC:75.

3. Engineering Properties of Processed C&D Waste Aggregates (20-6.3 mm size):

4. Properties of C&D Waste Powder (<6.3 mm size):

Important Notes:

• Crushing to ≤75 mm is preferred; larger particles (up to 300 mm) allowed only with field compaction proof.
• C&D waste embankments are prone to erosion; side slopes must be protected with earth cover.
• **Maximum φ

Granular Sub-base Construction Using RCA (IRC 121 - Clause 7.3)

• Material: Crushed Cement Concrete (RCA) from damaged slabs only.
• Gradation: RCA must conform to WBM aggregate gradations as per Table 18 below.

• Layer Thickness: Max 75 mm per compacted layer.
• Compaction: Use tandem or vibratory rollers with light water sprinkling.
• Properties: RCA has higher water absorption (up to 7%), lower specific gravity (~2.3-2.5), and slightly inferior strength compared to natural aggregates (see Table 6 & 9).
• Use: Suitable for sub-base; for base courses, RCA must meet MORTH specs (strength, gradation, soundness).

Key Engineering Properties of RCA (Typical Ranges)

Summary Flow of RCA Sub-base Construction

flowchart TD
    A[Source: Demolished Cement Concrete] --> B[Crushing to Specified Gradation]
    B --> C[Screening & Gradation Check (Table 18)]
    C --> D[Layer-wise Spreading (Max 75 mm)]
    D --> E[Compaction with Vibr

RA Usage in Granular Sub-base (GSB) Layer as per IRC 121

Key Points from Clause 7.4:

• RA (Recycled Aggregate) from crushed C&D waste is free-draining with good CBR.
• Avoid mixing with clayey soil to keep it non-plastic.
• Gradation may not meet MORTH/MORD specs initially.
• Mechanical stabilization (mixing with gravel/moorum/sand) per IRC:SP:89 can achieve desired gradation.
• Stabilized RA must meet gradation, plasticity, and strength requirements of MORTH/MORD for GSB.

Gradation Requirements (from Table 18, Clause 7.3 for RCA in Sub-base):

Specifications Summary:

• Layer thickness: Max 75 mm per compacted layer.
• Compaction: Tandem or vibratory rollers with light water sprinkling.
• Strength: RA should meet CBR and strength criteria as per MORTH/MORD.
• Use: Suitable for GSB layer after mechanical stabilization if needed.

Mechanical Stabilization Concept (IRC:SP:89)

flowchart LR
    RA[Crushed C&D Waste (RA)] --> Mix[Mix with Gravel/Moorum/Sand]
    Mix --> StabilizedRA[Mechanically Stabilized RA]
    StabilizedRA --> Test[Check Gradation, Plasticity, Strength]
    Test -->|Meets Specs| Use[Use in GSB Layer]
    Test -->|Fails Specs| Modify[Adjust Mix or Crushing Process]
    Modify --> Mix

In brief: Use mechanically stabilized RA with proper gradation and strength as per MORTH/MORD specs. Follow gradation tables, layer thickness

Key Specifications & Formulas for C&D Waste in Bound/Cement Stabilised Sub-Base/Base Course (IRC 121 Clauses 7.5 & 7.6):

1. Material Use & Treatment

• C&D waste (brick bats, rubble) usually fails strength criteria for granular bases (WBM/WMM).
• Stabilisation with cement or cement + fly ash/slag is necessary.
• Both coarse aggregates and fine powders from crushed C&D waste can be stabilised.

2. Strength Requirements

3. Mix Design & Durability

• Follow IRC:SP:89 for mix design and durability testing.
• Determine cement percentage via trial mixes to meet strength & durability.
• Durability tests per IRC:SP:89 ensure long-term performance.

4. Reference for Gradation & Strength

• Use MORTH/MORD specs, IRC:SP:72, and IRC:SP:89 for detailed gradation and strength criteria.

Summary Formula for Compressive Strength (Unconfined):

[ f_c = \frac{P}{A} ]

• (f_c) = compressive strength (MPa)
• (P) = load at failure (N)
• (A) = cross-sectional area (mm²)

flowchart TD
    A[C&D Waste] --> B[Crushing]
    B --> C[Coarse Aggregates + Powder]
    C --> D[Mix with Cementitious Admixtures]
    D --> E[Stabilised Layer]
    E --> F{Layer Type}
    F -->|Sub-base| G[Min 1.7 MPa @ 7 days]
    F -->|Base Course| H[Min 3.0 MPa @ 7 days]

In brief: Stabilise crushed C&D

IRC 121 - C&D Waste for Granular Base Course (Clause 7.6)

Key Specifications & Properties

• Use: Recycled Concrete Aggregate (RCA) can be used in granular base courses (WBM, WMM) if it meets MORTH/MORD specs depending on traffic:

  • > 2 MSA: Follow MORTH specs
  • < 2 MSA: Follow MORD specs

• Recycled Aggregate (RA): Suitable for lower base courses in rural roads if it meets:

  • Gradation
  • Strength
  • Water absorption
  • Soundness

Engineering Properties of Processed C&D Waste (20-6.3 mm size)

Finer Fraction (< 6.3 mm) Properties

Notes:

• Strength of RA is generally inferior to RCA.
• Ensure gradation and strength parameters conform to relevant standards before use.
• Water absorption and soundness tests are critical for durability assessment.

flowchart TD
    A[C&D Waste] --> B{Size}
    B --> |>6.3 mm| C[Coarse Aggregate]
    B --> |<6.3 mm| D[Finer Fraction]
    C -->

Key Specifications and Guidelines for RA and RCA Usage in Cement Concrete Pavement/Paving Blocks/Kerb Stones (IRC 121 - Clause 7.7 & 4.75):

• Replacement Limits:

  • RCA can replace up to 30% of natural mineral aggregates (NMA) in PCC pavement (grades up to M30) for low traffic (<200 vehicles/day).
  • For kerb stones and paving blocks (light traffic), RCA can replace up to 100% of NMA if compressive strength at 28 days meets specifications.
  • Powdered C&D waste can replace 20-25% of natural sand in dry lean concrete (DLC) and roller compacted concrete pavement (RCCP) up to M20 grade.

• Strength Considerations:

  • RCA usage beyond 30% or in grades above M30 is not recommended for pavements.
  • Mix design must ensure combined gradation of RCA + NMA meets specified gradation.
  • Concrete mix design and quality control should follow IRC and MORTH/MORD guidelines.

• Mixing Process:

  • Adopt Two Stage Mixing for concrete with RCA/RA:
    1. Mix aggregates + half water (60s)
    2. Add cement (30s)
    3. Add remaining water (120s)

• Typical Compressive Strength (Table 16):

• Quality Requirements:
  • RA/RCA must be free from deleterious materials (organic, plastics, chlorides, sulphates).
  • Water absorption of RCA ~4.5% (coarse), ~13-14.8% (fine).

IRC 121 - Quality Management: Key Points

The code emphasizes stringent Quality Management for processed Construction & Demolition (C&D) waste used in road construction. Key aspects include:

Quality Control Parameters (from Tables 4 & 5)

Quality Management Highlights:

• Material Testing: Regular testing of physical and mechanical properties (ACV, AIV, CBR, compaction) to ensure compliance.
• Process Control: Monitoring crushing, grading, and washing processes to maintain consistency.
• Documentation: Maintain records of test results, material sources, and processing methods.
• Compliance: Adherence to specified limits for strength, durability, and moisture content.

Summary Diagram: Quality Management Process for C&D Waste

flowchart TD
    A[Raw C&D Waste] --> B[Processing Plant]
    B --> C[Material Testing]
    C --> D{Meets Specifications?}
    D -- Yes --> E[Approved for Use]
    D -- No --> F[Reprocessing / Reject]
    E --> G[Documentation & Records]

Note: These parameters ensure durable, safe, and sustainable use of C&D waste in road construction per IRC 121 guidelines.

IRC 121: Successful Case Studies on Processed C&D Waste in Road Sector

While IRC 121 Annexure-I (p.26) details successful case studies, key summarized engineering properties and specifications from the code are:

Typical Properties of Processed C&D Waste Aggregates (20-6.3 mm)

Powdered C&D Waste (Fine Aggregate) Properties

RCA vs Natural Aggregates (NMA) Comparison

Key Specifications for Use:

• Use RCA and processed C&D waste in embankment, sub-base, base courses as per Sections 7.2 to 7.7 (p.19-22).
• Quality control per Clause 7 (p.24).
• Design friction angle φ limited to 40° for safety.
• Ensure water absorption and crushing