Guidelines for the Design of Stabilized PavePart IIPart-II)
2018 Edition

Overview of IRC SP 89 Part 2: Cementitious Chemical Stabilizer Focus

This section introduces the use of cementitious chemical stabilizers (CCS) within pavement design.

Key Parameters:

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

Typical Pavement Sections & Design Considerations:

• Stabilized pavements incorporate CCS to enhance strength and longevity.
• Design includes detailed material characterization, mix formulation, and performance behavior analysis.
• Construction methods and acceptance protocols are outlined.

Sample Data Extract:

Design Calculation Highlights:

• Computations of stresses and strains at specified depths.
• Utilization of elastic modulus "E" values from Annexure-II B.
• Example mix design presented in Annexure-III B.

Simplified Flow of Stabilized Pavement Design Process:

flowchart TD
    A[Material Analysis] --> B[Mix Proportioning]
    B --> C[Construction Execution]
    C --> D[Performance Monitoring]
    D --> E[Product Acceptance]

For comprehensive formulas and mix design details, see Annexure-II B and Annexure-III B.

Acceptance Protocol for CCS Products (IRC SP 89 Part 2)

Essential Acceptance Requirements:

1. Product Documentation:

• Broad chemical composition details
• Manufacturing site information
• Records of successful field applications
• Comparative performance data versus traditional stabilizers like cement or lime
• Certificates for toxicity and heavy metal leaching tests (per Annexure-I)

2. Usage Certification:

• Certificates from country of origin including project documentation
• Indian usage certificates for past two years if available
• Success metrics and extent of use in governmental infrastructure
• Field performance evaluations under diverse climates such as sub-zero, snowy, and heavy rainfall environments

3. Proven Product Criteria:

• Test reports from Indian road projects under varied weathering
• Adoption of fatigue equations developed by reputed research bodies (IIT, NIT, CRRI)

Critical Testing Requirements (Clause 3.3):

• Toxicity and Leachate Testing: Mandatory to prevent environmental contamination as outlined in Annexure-I.
• Durability Evaluations:
  • Sub-base: Method 1, Clause 4.7.2, IRC:SP:89-2010
  • Base: Method 2, Clause 4.7.2, IRC:SP:89-2010 incorporating ASTM D-559 & D-560 for cyclic wetting/drying and freeze/thaw
• Material Properties Compliance: Per IRC:37, IRC:SP:89-2010, and MoRTH 2013 specifications

Summary Table for Required Acceptance Documents:

Reference: Toxicity Leaching Test (Annexure-I)

• Evaluates leaching of heavy metals and toxic elements
• Testing conducted at accredited laboratories including CSIR Lucknow

flowchart TD
    A[CCS Product Submission] --> B{Verify Product Documentation}
    B -->|Complete| C{Confirm Usage Certificates}
    B -->|Incomplete| D[Reject or Request Additional Info]

Material Characterization Guidelines as per IRC SP 89 Part 2

Soil Classification Based on Grain Size (Clause 2.36):

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

Standard UCS Test Mould Dimensions (Table A):

Correction Factors for UCS Results to 150 mm Cube Equivalent (Table B):

Additional Notes on Stabilizer Evaluation:

• Examine chemical composition, manufacturing origin, and field application history.
• Obtain certificates for usage internationally and within India (recent two years).
• Established products require field evaluation reports and may employ fatigue models from recognized institutes.

flowchart TD
    A[Soil Sampling] --> B[Grain Size Analysis]
    B --> C{Soil Classification}
    C -->|Fine-Grained| D[UCS Test with 100x50 mm Cylinder]
    C -->|Medium-Grained| E[UCS Test with 200x100 mm Cylinder]
    C -->|Coarse-Grained| F[UCS Test with 150 mm Cube]
    D --> G[Apply Correction Factors]
    E --> G
    F --> G
    G --> H[Standardized UCS Value for Design]

Design Approach for CCS/CS Stabilized Pavements According to IRC SP 89 Part 2

• Referenced Design Standard: Utilize IRC:37 for designing pavements using Cold Central Slurry (CCS) or Cold Stabilization (CS).

• Pavement Layer Combinations Addressed:

  • Stabilized base with stabilized sub-base
  • Stabilized base with granular sub-base
  • Granular base with stabilized sub-base

• Crack Relief Layer Recommendations (Clause 3.4): For traffic volumes ≥ 2 million standard axles (MSA), include a crack relief layer atop CCS/CS stabilized base:

  • Aggregate interlayer
  • Stress absorbing membrane interlayer (SAMI)
  • Emulsion or foam bitumen stabilized layer (per IRC:37)

• Elastic Modulus (E) Determination: Consult Annexure-II B for stabilized layer modulus essential to structural design.

• Reference Typical Sections & Mix Designs: See Annexure-III A (pavement sections) and Annexure-III B (mix design example).

Summary Table: Layer Combinations

Crack Relief Layer Options for 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 or Foam Bitumen Layer]

Note: For details on thickness design, loading, and material parameters, refer to IRC:37 and IRC SP 89 Part 2 annexures.

Construction Methodologies per IRC SP 89 Part 2 (2018 Edition)

• Reference: Clause 5, page 8
• Scope: Procedures for constructing pavements stabilized with Cement Concrete Slurry (CCS) or Cement Stabilized soil (CS).

Key Construction Guidelines

• Material Preparation: Achieve thorough blending of soil with stabilizing agents such as cement or lime.
• Moisture Management: Maintain optimum moisture content to facilitate efficient compaction.
• Layer Thickness: Adhere to designed thicknesses as per IRC:37 and Annexure-III.
• Compaction: Employ appropriate rollers (vibratory or pneumatic) to attain the required density.
• Curing: Ensure moisture retention for a minimum of 7 days to promote strength development.
• Quality Assurance: Conduct frequent field density checks and verify mix uniformity.

Relevant Annexures and Tables

Design Reference

• Follow IRC:37 design methods with cumulative damage considerations.
• Use Annexure-III for typical layer configurations.

flowchart TD
    A[Selection of Materials] --> B[Mixing with Stabilizers]
    B --> C[Moisture Regulation]
    C --> D[Spreading of Layers]
    D --> E[Compaction Process]
    E --> F[Curing Period]
    F --> G[Quality Control Procedures]

This workflow ensures durable and high-quality stabilized pavements.

Performance Attributes in IRC SP 89 Part 2: Key Parameters and Formulas

1. Elastic Modulus and Safety Considerations

• Average elastic modulus from laboratory four-point beam tests is approximately 2600 MPa.

• For design, apply a safety factor of 1.5:

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

• If beam test data is unavailable, estimate E from UCS correlations.

2. Poisson’s Ratio for Various Pavement Layers

3. Fatigue Parameters for Bituminous Surfacing

• At 35°C with VG40 bitumen, elastic modulus approximates 3000 MPa (per IRC:37).

4. Correlation Between Dynamic Modulus and Compressive Strength

• Dynamic modulus (in GPa) relates closely to compressive strength (MPa) for cement-treated materials.
• Suppliers should develop fatigue models validated by institutes like IIT.

5. Critical Locations for Stress and Strain

• Tensile stresses and strains are most critical at the bituminous layer, crack relief interlayer, and stabilized base or sub-base.
• Vertical strains in the subgrade are critical at the subgrade level.

6. Load and Coordinate Framework

• Load: Single wheel load set at 20,000 N; tyre pressure at 0.56 MPa.
• Coordinate system:
  • X-axis: transverse to traffic direction
  • Y-axis: direction of traffic flow
  • Z-axis: vertical downward (zero at surface)

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

Toxicity and Leaching Evaluation of Soil-Stabilizer Mixtures (IRC SP 89 Part 2)

Referenced Procedure: USEPA Toxicity Characteristic Leaching Procedure (TCLP) Method 1311, July 1992

Test Protocol and Parameters

• Sample Preparation:

  • Combine stabilizer with dried, sieved soil at recommended weight ratios.
  • Add water and mix thoroughly.
  • Cast samples in Proctor molds.
  • Prepare additional samples spiked with Cr, Ni, Cu, Pb as per IS 4332 Part 3.

• Extraction Conditions:

  • Leaching solution pH: 2.88 ± 0.05
  • Agitation: 30 ± 2 rpm
  • Duration: 18 ± 2 hours
  • Temperature: 23 ± 2°C
  • After extraction, filter leachate and analyze heavy metals by Atomic Absorption Spectrometry (AAS) following APHA 2005 standards.
  • Perform triplicate tests and report average values.

• Metals Monitored: Chromium, Nickel, Lead, Copper

• Acceptance Criteria: Compare measured concentrations against USEPA TCLP regulatory limits to determine hazardous classification.

Summary Table of TCLP Test Parameters

Additional Notes:

• Tests must be conducted at accredited facilities, e.g., CSIR labs like IITR Lucknow.
• Stabilized samples should be crushed, dried, and sieved prior to leaching.
• Materials exceeding limits require disposal in secured landfills or further treatment.

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

Durability Evaluation of Cementitious Stabilized Materials (IRC SP 89 Part 2)

Key Procedures:

1. Sample Preparation and Leaching Test (Clause 2.88):

• Stabilizer blended with dried and sieved soil at recommended ratios.
• Water containing spiking solution (Cr, Ni, Cu, Pb) added.
• Leaching performed using TCLP protocol: pH 2.88 ± 0.05, 30 ± 2 rpm agitation, 18 ± 2 hours, at 23 ± 2°C.
• Metal analysis via Atomic Absorption Spectroscopy.
• Triplicate tests and average results reported.
• Standards followed: IS 4332 Part 3 and USEPA TCLP 1311 (1992).

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

3. UCS Testing Mould Specifications:

4. Correction Factors for UCS Results to 150 mm Cube Equivalent:

5. Wetting and Drying Cycles (12 Cycles):

• Each cycle involves submerging samples in water, drying, and brushing with a wire brush applying 1.4 kg force for 18-20 vertical strokes.

Procedure for Calculating Elastic Modulus "E" per IRC SP 89 Part 2

Test Setup:

• Beam specimens supported with a span of three times the beam depth (3 × d).
• Load applied at third points in a 3-point bending configuration.
• Loading displacement rate approximately 1.2 mm/min or stress rate about 7 ± 0.4 kg/cm²/min.
• Specimens typically sized 500 × 100 × 100 mm or 300 × 75 × 75 mm.

Fundamental Formulas

1. Modulus of Rupture (Flexural Strength) R:

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

or including beam weight:

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

Where:

• (P) = maximum load (kg)
• (l) = span length (cm)
• (b) = beam width (cm)
• (d) = beam depth (cm)
• (W) = weight of beam (kg)

If the fracture occurs outside the middle third by ≤ 5% of the 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} ]

Where:

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

Additional Specifications:

• Poisson's ratio generally taken as 0.25 for cemented layers.
• Typical UCS values:
  • Lime-flyash-soil mix: 1.05 MPa
  • Soil cement: 0.70 MPa

Summary Table for Elastic Modulus Calculation Parameters

Typical Pavement Sections for Stabilized Pavements per IRC SP 89 Part 2

Highlights from Clause 4.3.1 and Annexure III:

• Design methodology follows IRC:37 including cumulative damage analysis.
• Multiple pavement section variants depending on material availability and design requirements.
• Stabilized layers provide enhanced strength and durability.
• Single wheel load used in design: 20,000 N with tyre pressure of 0.56 MPa.

Typical Pavement Layer Components:

• Surface Course: Bituminous or concrete wearing surface.
• Base Course: Either granular or stabilized (cement, lime, fly ash).
• Sub-base: Granular material to distribute load.
• Subgrade: Natural or improved soil layer.

Example Section from Annexure III:

Design Equation (Based on IRC:37):

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

Where:

• (a_i) = layer coefficients

• (D_i) = thickness of layer in cm

• (m_i) = drainage coefficients

• Incorporate cumulative damage factor (Z_R) based on wheel load repetitions.

Load and Stress Parameters:

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

Summary:

• Use IRC:37 design principles with stabilizer-specific parameters.
• Select typical sections as baseline, adjusting thickness and materials for local conditions.
• Validate stresses and strains via layered elastic theory.
• Employ proper construction techniques for stabilized layers.

flowchart TD
    A[Pavement Design] --> B[Layer Selection]
    B --> C[Thickness Determination]
    C --> D[Stress & Strain Analysis]
    D --> E[Construction Considerations]

Mix Design Example and Key Parameters from IRC SP 89 Part 2

1. Input Design Parameters

• Design Traffic: 50 Million Standard Axles (MSA)
• Subgrade CBR: 7%
• Elastic Modulus (E):
  • Laboratory beam test average: 2600 MPa
  • Design value with factor of safety 1.5: [ E_{design} = \frac{2600}{1.5} = 1733 \approx 1700 \text{ MPa} ]
• Poisson’s Ratio (ν):

2. Fatigue and Rutting Relationship

• Number of axle repetitions to produce 20 mm rut depth:

[ 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 downward (surface at Z=0)

Diagram of Pavement Layering and Strain Locations

graph TD
    A[Bituminous Concrete] --> B[Dense Bituminous Macadam]
    B --> C[Stabilized Base]
    C --> D[Sub-base Layer]
    D --> E[Subgrade Soil]

Recommended Equipment for In-Situ Spreading and Mixing per IRC SP 89 Part 2

Key Guidelines (Clause 5.2 and Annexure-IV)

• Mix-in-place Stabilization: Use specialized equipment capable of:

  • Crushing rocks and boulders on site
  • Pulverizing and homogenizing soil materials
  • Maintaining a uniform mixing depth and consistent operation

• Manual mixing is permitted only for low volume roads with mixing depths up to 100–120 mm.

• Plant-mix Stabilization: Ensure calibration of concrete batch mixers or WMM plants with CCS additives to achieve uniform blending.

• Importance of Mixing: Effective mixing is crucial, especially since admixture rates may be below 3%. Quality machinery guarantees intimate and uniform mixing.

Recommended Machinery Types (Annexure-IV):

• Tractor mounted spreaders
• Truck mounted spreaders
• Tractor power-driven mixers
• Self-powered mixers

Summary Table of Equipment Functions

Important Notes:

• Manual or agricultural mixing methods are prohibited except for shallow depth, low traffic roads.
• Calibration of plant mixers is essential to ensure homogeneous mixes.
• Machinery must provide uniform depth control and thorough mixing to achieve successful stabilization.

flowchart LR
    A[Additive Spreading] --> B[Mixing Equipment]
    B --> C[Crushing and Pulverizing]
    B --> D[Homogenizing Soil]
    C & D --> E[Uniform Depth and Mix]
    E --> F[Enhanced Soil Stabilization]

This ensures consistent quality of stabilized pavement layers as per IRC SP 89 Part 2.