Guidelines for the Design of Stabilized PavePart IIPart-II)

IRC SP 89 Part 2 - Introduction: Key Points

This part of IRC SP 89 focuses on cementitious chemical stabilizers (CCS) for pavement design.

Key Specifications:

• Single wheel load: 20,000 N
• Tyre pressure: 0.56 MPa

Typical Sections & Design:

• Stabilized pavements use CCS for improved strength and durability.
• Design methodology includes material characterization, mix design, and performance behavior.
• Construction practices and acceptance mechanisms are detailed.

Important Tables & Data (Extract):

Design Formula Highlights:

• Pavement stresses and strains are calculated at various depths (Z).
• Use elastic modulus "E" from Annexure-II B for design.
• Mix design example provided in Annexure-III B.

Summary Flow of Stabilized Pavement Design:

flowchart TD
    A[Material Characterization] --> B[Mix Design]
    B --> C[Construction Practices]
    C --> D[Performance Evaluation]
    D --> E[Acceptance Mechanism]

For detailed formulas and mix design, refer to Annexure-II B and Annexure-III B of IRC SP 89 Part 2.

Mechanism of Acceptance for CCS (IRC SP 89 Part 2)

Key Acceptance Criteria:

1. Base Document of Product
   Must include:

   • Broad chemical composition
   • Manufacturing location
   • Successful field applications
   • Comparative test results with conventional stabilizers (cement/lime)
   • Toxicity and heavy metal leaching test certificates (Annexure-I)

2. Certificate of Usage

   • Usage certificate from country of origin with project reports
   • Indian usage certificate (last 2 years) if applicable
   • Success rate and quantum of work in government projects
   • Field evaluation reports under varied climatic conditions (sub-zero, snow-bound, high rainfall)

3. For Proven Products

   • Test reports from Indian roads under different weathering conditions
   • Fatigue equations developed by reputed institutes (IIT, NIT, CRRI) may be used

Important Test Requirements (Clause 3.3)

• Toxicity & Leaching Tests: Mandatory as per Annexure-I to avoid environmental contamination.
• Durability Tests:
  • Sub-base: Method 1, Clause 4.7.2, IRC:SP:89-2010
  • Base: Method 2, Clause 4.7.2, IRC:SP:89-2010 (ASTM D-559 & D-560 for wetting/drying and freezing/thawing cycles)
• Material Properties: Per IRC:37, IRC:SP:89-2010, and MoRTH 2013 specifications.

Summary Table for Acceptance Documents

Reference: Toxicity Leaching Test (Annexure-I)

• Tests heavy metals and toxic elements leachability
• Conducted at CSIR Lucknow or accredited labs

flowchart TD
    A[Start: CCS Product Submission] --> B{Check Base Document}
    B -->|Complete & Verified| C{Check Certificate of Usage}
    B -->|Incomplete| D[Reject or Request

Material Characterization per IRC SP 89 Part 2

Soil Classification by Grain Size (Clause 2.36)

• Fine-Grained: ≥ 90% passing 2.36 mm IS sieve
• Medium-Grained: ≥ 90% passing 20 mm IS sieve
• Coarse-Grained: ≥ 90% passing 40 mm IS sieve

Standard Moulds for UCS Test (Table A)

Correction Factors for UCS Results (Table B)

Notes on Stabilizer Evaluation

• Check chemical composition, manufacturing origin, field application history, and toxicity.
• Review certificates of usage both internationally and in India (last 2 years).
• Proven products require field evaluation reports and may use specialized fatigue equations from reputed institutes.

flowchart TD
    A[Soil Sample] --> B[Grain Size Analysis]
    B --> C{Soil Type}
    C -->|Fine-Grained| D[UCS Test: 100x50 mm Cylinder]
    C -->|Medium-Grained| E[UCS Test: 200x100 mm Cylinder]
    C -->|Coarse-Grained| F[UCS Test: 150 mm Cube]
    D --> G[Apply Correction Factor]
    E --> G
    F --> G
    G --> H[Standardized UCS Value]
``

Design Methodology for CCS/CS Stabilized Pavements (IRC SP 89 Part 2)

• Reference Standard: Follow IRC:37 design methodology for stabilized pavements using Cold Central Slurry (CCS) or Cold Stabilization (CS).

• Pavement Types Considered:

  • Stabilized Base + Stabilized Sub-base
  • Stabilized Base + Granular Sub-base
  • Granular Base + Stabilized Sub-base

• Crack Relief Layer (Clause 3.4):
  For traffic ≥ 2 MSA, provide a crack relief layer on CCS/CS stabilized base layer:

  • Aggregate Interlayer
  • Stress Absorbing Membrane Interlayer (SAMI)
  • Emulsion stabilized or foam bitumen layer (per IRC:37)

• Elastic Modulus (E): Refer Annexure-II B for determination of elastic modulus of stabilized layers, essential for structural design.

• Typical Sections & Mix Design:
  See Annexure-III A (typical pavement sections) and Annexure-III B (mix design example) for practical guidance.

Summary Table: Pavement Layer Combinations

Crack Relief Layer Options (Traffic ≥ 2 MSA)

graph LR
A[CCS/CS Stabilized Base] --> B{Crack Relief Layer}
B --> C[Aggregate Interlayer]
B --> D[Stress Absorbing Membrane Interlayer (SAMI)]
B --> E[Emulsion Stabilized / Foam Bitumen Layer]

Note: For detailed thickness design, traffic loading, and material properties, consult IRC:37 and relevant annexures in IRC SP 89 Part 2.

IRC SP 89 Part 2 (2018) – Construction Practices: Key Points

• Reference Section: Clause 5 (Page 8)
• Scope: Guidelines for construction of stabilized pavements using Cement Concrete Slurry (CCS) or Cement Stabilized Soil (CS).

Key Construction Practices

• Material Preparation: Proper mixing of soil with stabilizers (cement, lime, etc.) ensuring uniformity.
• Moisture Control: Maintain optimum moisture content for effective compaction.
• Layer Thickness: Follow design thickness as per IRC:37 and Annexure-III typical sections.
• Compaction: Use suitable rollers (vibratory, pneumatic) to achieve specified density.
• Curing: Maintain moisture for at least 7 days to ensure strength gain.
• Quality Control: Frequent field density tests and mix uniformity checks.

Important Tables & Annexures

Design Reference

• Follow IRC:37 design methodology including cumulative damage analysis.
• Use Annexure-III for typical pavement layer combinations.

flowchart TD
    A[Material Selection] --> B[Mixing with Stabilizer]
    B --> C[Moisture Control]
    C --> D[Layer Spreading]
    D --> E[Compaction]
    E --> F[Curing]
    F --> G[Quality Control]

This flow ensures durable, well-performing stabilized pavements per IRC SP 89 Part 2.

IRC SP 89 Part 2: Performance Behavior - Key Formulas & Specifications

1. Elastic Modulus (E) & Safety Factor

• Laboratory 4-point beam test gives average E = 2600 MPa.

• Design E considering safety factor 1.5:

  [ E_{design} = \frac{2600}{1.5} = 1733 \text{ MPa (approx. 1700 MPa)} ]

• If beam test unavailable, use UCS test correlation for E.

2. Poisson's Ratio for Pavement Layers

3. Fatigue Criteria for Bituminous Surfacing

• At 35°C with VG40 bitumen, Elastic Modulus = 3000 MPa (IRC:37 reference).

4. Relationship: Dynamic Modulus vs Compressive Strength

• Dynamic modulus (GPa) correlates with compressive strength (MPa) for cement-treated materials.
• Stabilizer suppliers should develop fatigue equations verified by institutes like IIT.

5. Typical Critical Locations for Strain & Stress

• Tensile strain/stress critical at bituminous layer, crack relief interlayer, stabilized base/sub-base.
• Vertical subgrade strain critical at subgrade level.

6. Load & Coordinate System

• Load: Single wheel load = 20,000 N; tyre pressure = 0.56 MPa.
• Global coordinate system:
  • X-axis: transverse to traffic
  • Y-axis: direction of travel
  • Z-axis: vertical downward (Z=0 at surface)

flowchart TD
    A[Load Application] --> B[Stress & Strain Distribution]
    B --> C{Critical Locations}
    C --> D[Bituminous Layer]
    C --> E[Crack Relief Interlayer]
    C --> F[Stabilized Base/Sub-base]
    C --> G[Subgrade]
    B

Toxicity Leaching Testing on Stabilizers Mixed with Soil (IRC:SP:89 Part 2)

Reference: USEPA TCLP (Toxicity Characteristics Leaching Procedure) Method 1311 (July 1992)

Key Specifications & Procedure

• Sample Preparation:

  • Mix stabilizer with dried, sieved soil at recommended w/w ratio.
  • Add water and mix thoroughly.
  • Cast in Proctor molds.
  • Prepare separate samples with spiking solution of Cr, Ni, Cu, Pb (per IS 4332 Part 3).

• Leaching Test Conditions:

  • Leaching solution pH: 2.88 ± 0.05
  • Extraction: Closed vessels, 30 ± 2 rpm, 18 ± 2 hours, ambient temperature (23 ± 2°C)
  • Post-extraction: Filter leachate, analyze metals via Atomic Absorption Spectrometry (AAS) (APHA 2005 protocols)
  • Triplicate tests; report mean values.

• Metals Tested: Chromium, Nickel, Lead, Copper

• Acceptance Criteria: Compare metal concentrations with USEPA TCLP limits to classify material as hazardous or non-hazardous.

Summary Table: TCLP Test Parameters

Notes:

• Testing must be done by accredited labs (e.g., CSIR institutes like IITR Lucknow).
• Stabilized samples must be crushed, dried, and sieved before leaching.
• If metal leachate exceeds limits, material requires secure landfill or further treatment.

flowchart TD
    A[Prepare Soil-Stabilizer Mix] --> B[Cast in Proctor Moulds]
    B --> C[Add Leaching Solution (pH 2.88)]
    C --> D[Extraction: 30 rpm, 18 hrs, 23°C]
    D --> E[Filter Leachate

Durability Testing for Stabilized Materials (IRC SP 89 Part 2)

Key Specifications & Procedures:

1. Sample Preparation & Leaching Test (Clause 2.88)

• Stabilizer mixed with dried, sieved soil (recommended w/w ratio).
• Water with spiking solution (Cr, Ni, Cu, Pb) added.
• Leaching using TCLP protocol (pH 2.88 ± 0.05, 30 ± 2 rpm, 18 ± 2 hrs, 23 ± 2℃).
• Analyze metals by Atomic Absorption Spectrometer.
• Triplicate tests; mean results reported.
• Follow IS 4332 Part 3 and USEPA TCLP 1311 (1992).

2. Durability Tests (Wet-Dry & Freeze-Thaw) - IS:4332 Part IV

3. Mould Sizes for UCS Testing

4. Correction Factors for UCS to 150 mm Cube

5. Wetting and Drying Cycles (12 cycles)

• Each cycle: Submerge in water, dry, brush with wire brush (1.4 kg force, 18-20 vertical strokes).

Determination of Elastic Modulus "E" — IRC SP 89 Part 2

Test Setup:

• Beam placed on supports spaced 3 × depth (d) apart.
• Load applied at third points (3-point bending).
• Loading rate: ~1.2 mm/min displacement or stress rate 7 ± 0.4 kg/cm²/min.
• Specimen sizes: 500×100×100 mm or 300×75×75 mm.

Key Formulas

1. Modulus of Rupture (Flexural Strength) R:

[ R = \frac{P l}{b d^2} \quad \text{(neglecting beam weight)} ]

[ R = \frac{(P + \frac{3W}{4}) l}{b d^2} \quad \text{(considering beam weight)} ]

• (P) = max load (kg)
• (l) = span length (cm)
• (b) = width (cm)
• (d) = depth (cm)
• (W) = specimen weight (kg)

If fracture is outside middle third by ≤5% span:

[ a = \text{distance from fracture to nearest support} ]

2. Elastic Modulus (E):

[ I = \frac{b d^3}{12} ]

[ E = \frac{P a (3L^2 - 4a^2)}{24 I \delta} ]

• (P) = load at corresponding deflection (\delta) (N)
• (a = \frac{L}{3}) (distance from support to load point)
• (L) = span length (mm)
• (b, d) = beam width and depth (mm)
• (\delta) = deflection at load (P) (mm)
• (I) = moment of inertia (mm⁴)

Important Specifications

• Poisson's ratio: 0.25 for cemented layers.
• Unconfined compressive strength for mix types:
  • Lime-flyash-soil: 1.05 MPa
  • Soil cement: 0.70 MPa

Summary Table for E-Value Calculation

| Parameter |

IRC SP 89 Part 2: Typical Sections for Stabilized Pavements

Key Points from Clause 4.3.1 & Annexure III:

• Design follows IRC:37 procedure including cumulative damage analysis.
• Multiple typical pavement sections are possible depending on material availability.
• Stabilized layers improve strength and durability.
• Single wheel load considered: 20,000 N with tyre pressure 0.56 MPa.

Typical Section Components:

• Surface Course: Bituminous or concrete wearing layer.
• Base Course: Granular or stabilized layer (cement/lime/fly ash).
• Sub-base: Granular material for load distribution.
• Subgrade: Natural soil or improved soil.

Example Typical Section (from Annexure III):

Design Formula (IRC:37 based):

• Structural Number (SN):

[ SN = a_1 D_1 + a_2 D_2 m_2 + a_3 D_3 m_3 ]

Where:

• (a_i) = layer coefficient

• (D_i) = thickness of layer (cm)

• (m_i) = drainage coefficient

• Use cumulative damage factor (Z_R) from wheel load repetitions.

Load & Stress Parameters (from provided table snippet):

• Single wheel load: 20 kN
• Tyre pressure: 0.56 MPa
• Stress components: (\sigma_z, \sigma_r, \tau_{rz}) and strains (\epsilon_z, \epsilon_r, \epsilon_\theta) vary with depth (Z).

Summary:

• Follow IRC:37 design procedure with stabilizer parameters.
• Use typical sections as starting points, adjust thickness/material based on local conditions.
• Validate stresses and strains using layered elastic theory (as per table data).
• Ensure proper construction practices for stabilized layers.

flowchart TD
    A[Pavement Design] -->

IRC SP 89 Part 2 - Mix Design Example: Key Formulas & Specs

1. Input Parameters

• Design Traffic: 50 MSA (Million Standard Axles)
• Subgrade CBR: 7%
• Elastic Modulus (E):
  • Stabilized Base (lab 4-point beam test): 2600 MPa
  • Design E (with FOS 1.5):
    [ E_{design} = \frac{2600}{1.5} = 1733 \approx 1700 \text{ MPa} ]
• Poisson's Ratio (ν):

2. Fatigue & Rutting Equation

• Number of axles to cause rutting of 20 mm:
  [ N = 4.1656 \times 10^{-8} \times \left(\frac{1}{\varepsilon_v}\right)^{4.5337} ] Where:
• (N) = cumulative standard axles
• (\varepsilon_v) = vertical subgrade strain (microstrain)

3. Typical Layer Thickness (mm)

4. Coordinate System for Analysis

• X-axis: Transverse to traffic
• Y-axis: Direction of traffic
• Z-axis: Vertical downwards (Z=0 at surface)

Summary Diagram: Pavement Layering & Strain Locations

graph TD
    A[Bituminous Concrete] --> B[Dense Bituminous

IRC SP 89 Part 2: Specialized In-Situ Spreading & Mixing Machinery for Stabilization

Key Specifications (Clause 5.2 & Annexure-IV)

• Mix-in-Place Stabilization: Use specialized machinery capable of:

  • In-situ rock/boulder crushing, pulverizing, and homogenizing.
  • Maintaining constant depth and uniform operation.
  • Manual mixing allowed only for low volume roads with mixing depth ≤ 100-120 mm.

• Plant-mix Stabilization: Calibrate plant mixers (Concrete batch mix/WMM) with CCS for homogeneity.

• Mixing Importance: Effective mixing is critical as admixture dosage can be <3%. Quality equipment ensures intimate mixing.

Recommended Machinery Types (Annexure-IV)

• Tractor Mounted Spreaders
• Truck Mounted Spreaders
• Tractor Power Driven Mixers
• Self Power Driven Mixers

Summary Table (Mixing Equipment Features)

Important Notes:

• Manual/agriculture-based mixing is not permitted except for shallow depth low volume roads.
• Calibration of plant mixers is essential for homogeneity.
• Machinery must ensure uniform depth and thorough mixing for successful stabilization.

flowchart LR
    A[Additive Spreading] --> B[Mixing Machinery]
    B --> C[Crushing & Pulverizing]
    B --> D[Homogenizing Soil]
    C --> E[Uniform Depth]
    D --> E
    E --> F[Improved Soil Stabilization]

This ensures consistent soil stabilization quality per IRC SP 89 Part 2 guidelines.