Guidelines for the Use of High-Performance Concrete in Bridges

IRC SP 70: Introduction - Key Specifications & Tables

Concrete Grades & Strength (Clause 4.6.1, Table 2)

Cement & Water Requirements

• Minimum cement content: 380 kg/m³ (including mineral admixtures)
• Maximum cement content: 450 kg/m³ (excluding mineral admixtures)
• Water/(cement + cementitious materials) ratio: ≤ 0.33 (max 0.40)

Workability (IS 1199)

*For Very High, flow test per IS 9103 recommended.

Durability & Acceptance

• Water to conform to IRC:21-2000 Clause 302.4.
• Additional durability tests (e.g., Water Permeability DIN 1048 Pt 5, Initial Surface Absorption BS 1881 Pt 5) may be specified based on exposure severity.
• Basic permissible stresses for concrete grades ≤ M60 as per IRC:21 Table 9.
• For grades > M60, refer to IRC:18 or international codes.

References

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

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

IRC SP 70 - Scope: Key Specifications & Tables

Scope Overview:

• Applies to high strength concrete grades M40 to M80 for bridges.
• Concrete properties, permissible stresses, and design parameters for grades > M60 require specialized literature.
• Covers materials, mix design, strength, workability, durability, and acceptance criteria.

Key Tables & Specifications

Important Formulas/Concepts

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

  • ( f_{ck} ) = characteristic compressive strength
  • ( k = 1.64 ) (for 5% failure probability)
  • ( \sigma ) = standard deviation from site tests

• Water/Cementitious Materials Ratio (w/cm):
  [ w/cm \leq 0.33 \quad \text{(generally)}; \quad w/cm \leq 0.40 \quad \text{(max)} ]

References for Further Design

• IRC:21-2000 for basic permissible stresses (up to M60)
• IRC:18-2000 for prestressed concrete design
• IS codes for materials and testing (IS 383, IS 1199, IS 9103,

IRC SP 70 — Terminology Key Points

The terminology section (Clause 3) defines essential terms related to concrete grades, materials, and properties used in bridge construction per IRC standards.

Key Specifications & Tables:

• Concrete Strength Grades (Table 2):

• Cement Content:

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

• Water-Cementitious Materials Ratio:
  Should not exceed 0.33, max 0.40 in any case.

• Workability (IS:1199 slump values):

*For Very High, flow test per IS:9103 recommended.

Additional Notes:

• Concrete strength is defined as the strength below which not more than 5% of test results fall.
• Basic permissible stresses for concrete up to M60 are per IRC:21 Table 9.
• For grades above M60, refer to specialized literature or international codes.
• Acceptance and durability tests per IRC:21 Clauses 302.10 & 302.11 apply.

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

IRC SP 70 - Key Specifications & Formulas for Materials

1. Concrete Grades & Strengths

• Cement content: ≥ 380 kg/m³ (incl. mineral admixtures), max 450 kg/m³ (excluding mineral admixtures)
• Water/(cement + cementitious materials) ratio: ≤ 0.33 (max 0.40)
• Workability (Slump in mm):
  • Low: 25-50
  • Medium: 50-100
  • High: 100-150
  • Very High: 150-200 (use flow test as per IS:9103)

2. Cement Types (IS Standards)

• Use Pozzolana Cement only in plain concrete.
• Special care for sulphate resistance with low C2A content cement.

3. Aggregates

• Must conform to IS:383 and IS:2386.
• Coarse Aggregate max size limited by:
  • ≤ 1/4 minimum member thickness
  • ≤ (min lateral clear distance between reinforcements - 10 mm)
  • ≤ (min clear cover to reinforcement - 10 mm)
  • Nominal max size ≤ 20 mm
• Fine Aggregate: Zone II or III per IS:383 preferred.

Basic Permissible Stresses in Concrete (IRC SP 70 referencing IRC:21)

• For concrete grades up to M60, permissible stresses are per Table 9 of IRC:21 (not fully reproduced here, but typically include):

  • Permissible compressive stress in concrete under working loads ≈ 0.4 to 0.6 × fck (characteristic compressive strength)
  • Permissible tensile stress ≈ 0.06 to 0.1 × fck
  • Permissible shear stress ≈ 0.1 to 0.2 × fck

• For grades above M60 (M65, M70, etc.), IRC:21 and IRC:18 do not apply; specialized literature or international codes should be consulted.

Key Parameters from IRC:21 (Summary)

Additional Durability Tests (Clause 4.12.2)

• Water Permeability test (DIN 1048 Part 5-1991)
• Initial Surface Absorption test (BS 1881 Part 5)

Permissible values depend on exposure severity.

References for Detailed Values

• IRC:21-2000 Section III for plain and reinforced concrete
• IRC:18-2000 for prestressed concrete (up to M60)
• International Codes for HPC > M60 (e.g., ACI 363R, Eurocode 2)

flowchart TD
    A[Concrete Grade (M40 to M60)] --> B[Use IRC:21 Table 9]
    B --> C[Permissible Compressive Stress ≈ 0.45 fck]
    B --> D[

IRC SP 70 - References: Key Specifications & Tables

1. Codes & Standards Referenced

• IRC:18-2000 — Design criteria for prestressed concrete road bridges (post-tensioned).
• IRC:21-2000 — Standard specifications for road bridges (plain & reinforced concrete).
• IS Codes for materials & testing (e.g., IS 383, IS 455, IS 1199, IS 2386, IS 8112, IS 9103).
• International Standards: BS 1881 Pt.5 (surface absorption), DIN 1048 Pt.5 (water permeability), ASTM C1202 (chloride permeability).

2. Concrete Grades & Strengths

3. Mix Design Parameters

• Cement content: ≥ 380 kg/m³, max 450 kg/m³ (excluding mineral admixtures).
• Water/(cement + cementitious materials) ratio: max 0.40, preferably ≤ 0.33.
• Workability (Slump in mm):

*For very high workability, use flow test per IS:9103.

4. Durability Testing (Clause 302.11 IRC:21)

• Water permeability (DIN 1048 Pt.5).
• Initial surface absorption (BS 1881 Pt.5).
• Chloride permeability (ASTM C120