Guidelines for the Use of High-Performance Concrete in Bridges
2005 Edition

IRC SP 70 Overview - Core Specifications & Data

Concrete Grade Strengths (Clause 4.6.1, Table 2)

Cement and Water Specifications

• Minimum cement content: 380 kg/m³ (including mineral admixtures)
• Maximum cement content: 450 kg/m³ (excluding mineral admixtures)
• Water to cementitious material ratio: ≤ 0.33 (maximum limit 0.40)

Workability (per IS 1199)

*For very high slump, flow testing according to IS 9103 is advised.

Durability and Acceptance Criteria

• Water must comply with IRC:21-2000 Clause 302.4.
• Additional durability tests such as Water Permeability (DIN 1048 Part 5) and Initial Surface Absorption (BS 1881 Part 5) may be required based on exposure conditions.
• Basic permissible stresses for concrete grades up to M60 are defined in IRC:21 Table 9.
• For grades exceeding M60, consult IRC:18 or international standards.

Key References

• IRC:18-2000, IRC:21-2000, IS 1199, IS 9103, IS 383, IS 455, IS 1489, BS 1881 Part 5, DIN 1048 Part 5, ASTM C1202

flowchart TD
    A[Concrete Grade] --> B[Compressive Strength (MPa)]
    B --> C{Strength Category}
    C

Scope of IRC SP 70: HPC in Bridge Engineering

Scope Details:

• Applicable to high strength concrete grades ranging from M40 up to M80 utilized in bridge design.
• For grades beyond M60, design parameters and stress limits require consultation of specialized literature.
• Includes guidance on materials, mix design, mechanical properties, workability, durability, and acceptance criteria.

Essential Specifications and Tables

Important Formulas

• Target Mean Strength (f_tm):
  [ f_{tm} = f_{ck} + k \times \sigma ] Where:

  • ( f_{ck} ) is characteristic strength
  • ( k = 1.64 ) for 5% failure probability
  • ( \sigma ) is standard deviation from test data

• Water to Cementitious Materials Ratio:
  [ w/cm \leq 0.33, \quad w/cm \leq 0.40 \quad \text{(maximum)} ]

Additional Design References

• IRC:21-2000 for permissible stresses (up to M60)
• IRC:18-2000 for prestressed concrete design
• Indian Standards for materials and testing (e.g., IS 383, IS 1199, IS 9103)

Key Terms in IRC SP 70 (Clause 3) Related to HPC in Bridges

This section elaborates on terminology concerning concrete grades, constituent materials, and relevant properties as per IRC guidelines.

Key Data Tables:

• Concrete Strength Grades (Table 2):

• Cement Content Limits:

  • Minimum: 380 kg/m³ including mineral admixtures
  • Maximum: 450 kg/m³ excluding mineral admixtures

• Water to Cementitious Ratio:

  • Should not surpass 0.33, with an absolute maximum of 0.40

• Workability Slump Values (IS 1199):

*Flow testing per IS 9103 is advised for very high workability.

Additional Points:

• The characteristic strength is defined such that only 5% of test results fall below it.
• Permissible stresses for concrete up to M60 are given in IRC:21 Table 9.
• Consult specialized or international codes for grades exceeding M60.
• Durability and acceptance tests are outlined in IRC:21 Clauses 302.10 & 302.11.

flowchart TD
    A[Concrete Grade] --> B{Strength (MPa)}
    B -->|M40| C[40]
    B -->|M60| D[60]
    B -->|M80| E[80]
    F[Water-Cementitious Ratio] --> G[Max 0.33 (typical)]
    F --> H[Max 0.40 (absolute)]
    I[Workability] --> J[Low: 25-50 mm slump]

Material Specifications per IRC SP 70 for HPC

1. Concrete Grade Strengths

• Cement content should be ≥ 380 kg/m³ (including mineral admixtures) and not exceed 450 kg/m³ (excluding mineral admixtures).
• Water to cementitious materials ratio must be ≤ 0.33, with a maximum allowable of 0.40.
• Workability as slump in mm:
  • Low: 25-50
  • Medium: 50-100
  • High: 100-150
  • Very High: 150-200 (flow tests as per IS 9103 recommended)

2. Cement Types (IS Standards)

• Pozzolana cement is recommended only for plain concrete applications.
• Sulphate resistance requires cement with low C2A content.

3. Aggregates

• Must comply with IS 383 and IS 2386 standards.
• Maximum size of coarse aggregate limited by:
  • ≤ 1/4 of the minimum thickness of the member
  • ≤ minimum lateral clear spacing between reinforcements minus 10 mm
  • ≤ minimum clear cover to reinforcement minus 10 mm
  • Nominal maximum size limited to 20 mm
• Fine aggregates should preferably be from Zone II or III as per IS 383.

Permissible Stress Limits in Concrete Following IRC SP 70 and IRC:21

• For concrete grades up to M60, the allowable stresses conform to IRC:21 Table 9, typically:

  • Permissible compressive stresses under service loads: approximately 40% to 60% of fck
  • Permissible tensile stresses: roughly 6% to 10% of fck
  • Permissible shear stresses: about 10% to 20% of fck

• For concrete grades above M60 (e.g., M65, M70), IRC:21 and IRC:18 standards are not applicable; consult specialized technical literature or international codes.

Summary of Key Parameters (IRC:21)

Additional Durability Assessments (Clause 4.12.2)

• Water permeability test (DIN 1048 Part 5-1991)
• Initial surface absorption test (BS 1881 Part 5)

Test limits vary based on environmental exposure.

References for Detailed Values

• IRC:21-2000 Section III for plain and reinforced concrete
• IRC:18-2000 for prestressed concrete (grades up to M60)
• International codes such as ACI 363R and Eurocode 2 for HPC grades exceeding M60

flowchart TD
    A[Concrete Grades M40-M60] --> B[Refer IRC:21 Table 9]
    B --> C[Permissible Compressive Stress ≈ 0.45 fck]
    B --> D[Permissible Tensile Stress ≈ 0.06 fck]

References Cited in IRC SP 70 for HPC in Bridges

1. Codes and Standards

• IRC:18-2000 — Design guidelines for prestressed concrete road bridges.
• IRC:21-2000 — Specifications for plain and reinforced concrete road bridges.
• Indian Standards for materials and testing: IS 383, IS 455, IS 1199, IS 2386, IS 8112, IS 9103, among others.
• International standards including BS 1881 Part 5 (surface absorption), DIN 1048 Part 5 (water permeability), ASTM C1202 (chloride permeability).

2. Concrete Grades and Target Strengths

3. Mix Design Parameters

• Cement content: Minimum 380 kg/m³, maximum 450 kg/m³ (excluding mineral admixtures).
• Water to cementitious materials ratio: Preferably ≤ 0.33, maximum 0.40.
• Workability (Slump in mm):

*For very high workability, flow test as per IS 9103 is recommended.

4. Durability Testing Requirements (Clause 302.11 IRC:21)

• Water permeability (DIN 1048 Part 5)
• Initial surface absorption (BS 1881 Part 5)
• Chloride permeability (ASTM C1202)