Code of Practice for Construction of Floor and Roof with Joists and Filler Blocks, Part 1: With Hollow Concrete Filler Blocks
1971 Edition

IS 6061 Part 1 (1971) – Overview and Fundamental Specifications

• Purpose: Code for floors and roofs using precast reinforced concrete joists with hollow cement concrete filler blocks.
• Benefits: Enhanced durability, fire resistance, thermal insulation, reduced dead weight, accelerated construction without shuttering.
• Restrictions: Unsuitable for floors exposed to impact or vibrations.
• Testing Protocols:
  • Minimum two blocks daily or two per thousand blocks tested for dimensional accuracy and compressive strength (Clause 2.1.2).
  • Compressive strength benchmark values referenced in Table B-2 (dimensions in mm).
• Floor Finishes (Clause 7.1.1):

  Finish Type	Relevant IS Standard
  Cement concrete tiles	IS 1443-1959
  Terrazzo	IS 2114-1962
  Rubber	IS 1197-1970
  Linoleum	IS 1198-1958
  PVC	IS 5318-1969
  Epoxy resin	IS 4631-1968
  Bitumen mastic	IS 1196-1968

Note: Final test results should be rounded in accordance with IS 2-1960.

flowchart LR
    PrecastJoists[Precast Reinforced Concrete Joists] --> HollowBlocks[Hollow Cement Concrete Filler Blocks]
    HollowBlocks --> FloorRoofConstruction[Floor and Roof Assembly]
    FloorRoofConstruction --> Advantages[Advantages: Durability, Fire Resistance, Thermal Insulation]
    FloorRoofConstruction --> Limitations[Limitations: No Impact or Vibration Loads]
    FloorRoofConstruction --> Testing[Test Requirements: Dimensions & Strength]

Refer Table B-2 of Clause 2.1.2 in IS 6061 Part 1 for detailed block sizes and strength values.

IS 6061 Part 1 – Scope: Essential Specifications and Testing

Scope Overview:

• Applies to hollow cement concrete filler blocks used within floor and roof construction.
• Specifies testing methods, dimensional allowances, and strength evaluation.

Testing and Dimensional Controls:

• Sample Frequency (Clause 2.1.2):

  • At least two blocks daily or two per 1000 blocks, whichever is fewer, must undergo testing.

• Dimensional Limits (Clause 1.2):

  • Height and breadth tolerance: ±1.5 mm
  • Length tolerance: +3.0 mm

Breaking Strength Evaluation (Table B-2):

Typical Hollow Block Details (Fig. 2):

• Standardized shape and size conforming to IS 6061.
• Must adhere to specified tolerances and strength requirements.

Associated IS Standards for Floor Finishes (Clause 7.1.1):

flowchart TD
    HollowBlocks[Hollow Cement Concrete Blocks] --> SampleTesting[Sampling for Tests]
    SampleTesting --> SampleQuantity{2 blocks/day or 2 per 1000}
    HollowBlocks --> DimensionalTolerance[Dimensional Tolerances]
    DimensionalTolerance --> HeightBreadth[±1.5 mm Height & Breadth]
    DimensionalTolerance --> Length[+3.0 mm Length]
    HollowBlocks --> StrengthTest[Compressive Strength Test]
    StrengthTest --> TestSamples[Minimum 2 blocks tested]

Consult IS 6061 Part 1 for full dimensional and testing procedures.

Design Principles for Precast RCC/Prestressed Concrete Joists with Hollow Filler Blocks (IS 6061 Part 1)

Important Design Aspects (Clauses 2 & 3)

• System Composition: Combination of precast reinforced or prestressed concrete joists, hollow cement concrete filler blocks, and cast-in-place RCC topping slab.
• Joist Spacing: Determined by structural design, spanning between walls or beams (Clause 6.1).
• Joist Detailing: Reinforcement and prestressing details provided in Appendix A (Clause 3.5).

Hollow Concrete Blocks (Clause 2.1.2)

• Testing Requirements: Minimum two blocks daily or per 1000 tested for dimensions and compressive strength.
• Block Dimensions: As per Fig. 2 (standard block sizes in mm).
• Compressive Strength: Refer to Table B-2 for minimum strength values.

Material and Construction Standards

• Aggregates to conform to relevant IS specifications.
• Concrete design to comply with IS 456.
• Proper storage and stacking recommended for all materials.

Example Breaking Strength Values:

(Refer actual IS 6061 Table B-2 for precise values)

flowchart LR
    PrecastJoists[Precast RCC/PSC Joists] --> Spacing[Placed at Designed Spacing]
    Spacing --> Span[Span Between Supports]
    Span --> HollowBlocks[Hollow Concrete Filler Blocks]
    HollowBlocks --> RCCDecking[In-situ RCC Decking]

Summary: Design joists as per Appendix A, install at specified spacing, utilize tested hollow blocks, and cast RCC topping following IS 456 and aggregate quality standards.

Material Specifications per IS 6061 Part 1 (1971 Edition)

1. Hollow Cement Concrete Blocks (Clause 2.1.2)

• Sampling frequency: At least two blocks per lot/day or two per 1000 blocks subjected to dimensional and strength tests.
• Measurement units: Millimeters.

2. Concrete Grade for Precast Joists (Clause 2.1)

• Concrete grade specified as M-200 according to IS 456:1964.

3. Flooring Finishes (Clause 7.1.1)

Referenced codes provide laying and finishing guidelines.

Material Testing Summary for Hollow Blocks

Refer IS 6061 Part II or IS 456 for reinforcement specifics and concrete standards.

flowchart TD
    ConcreteBlocks[Concrete Blocks] --> Sampling[Sampling: 2 blocks/day or 2 per 1000]
    Sampling --> Testing[Tests: Dimensions & Compressive Strength]
    Joists[Precast Joists] --> ConcreteGrade[M-200 Grade Concrete (IS 456)]
    FlooringFinishes --> CementTiles[IS 1443 Cement Tiles]
    FlooringFinishes --> Terrazzo[IS 2114 Terrazzo]
    FlooringFinishes --> Rubber[IS 1197 Rubber]
    FlooringFinishes --> Linoleum[IS 1198 Linoleum]
    FlooringFinishes --> PVC[IS 5318 PVC]
    FlooringFinishes --> Epoxy[IS 4631 Epoxy Resin]
    FlooringFinishes --> Bitumen[IS 1196 Bitumen Mastic]

Guidelines for Scheduling Construction Activities (IS 6061 Part 1)

1. Preparation of Supporting Structures (Clause 4.1):

   • Complete and properly cure walls, columns, beams, and frames prior to flooring or roofing work.
   • Provide a leveling bed of plain concrete, 75 mm thick, with a 1:2:4 mix over load-bearing walls as needed.
   • Ensure the top surface is finished level.
   • Coordinate locations for service pipes, conduits, and fixtures passing through the floor.

2. Concrete Specification for Joists (Clause 2.1):

   • Utilize M-200 grade concrete complying with IS 456-1964.

3. Precast Hollow Concrete Filler Blocks (Clause 3.6 & Appendix B):

   • Blocks must meet dimensional and compressive strength standards.
   • Testing frequency: minimum two blocks per day or per 1000 blocks.

Typical Plain Concrete Leveling Bed Specifications:

Workflow Overview:

flowchart TD
    StructuralElements[Complete Structural Elements] --> Curing[Cure Elements Thoroughly]
    Curing --> ConcreteBed[Provide Concrete Bed if Necessary]
    ConcreteBed --> Leveling[Finish Surface Level]
    Leveling --> ServiceFixings[Arrange Service Fixings]
    ServiceFixings --> FlooringWork[Commence Flooring/Roofing]

Summary: Ensure early finishing and curing of support structures, proper leveling with concrete bed, and service coordination before flooring/roofing. Use M-200 concrete for joists and verify filler blocks meet IS 6061 requirements.

Procedures for Storage, Transport, and Handling of Materials (IS 6061 Part 1)

Key Points:

• Preparation of Supporting Elements: Complete curing of walls, pillars, beams before flooring/roofing. Provide 75 mm thick plain concrete bed (1:2:4) over load-bearing walls if required; ensure level top surfaces (Clause 4.1).

• Handling Precast Joists (Clause 6.1):

  • Carefully lift joists from casting platforms.
  • Use temporary supports at designer-specified points during stacking and transport.
  • Stack on stable, level ground or platform.
  • When stacking multiple layers, ensure vertical alignment of props.

• Material Storage (Clause 5.1):

  • Follow IS 4082-1967 guidelines for storage of cement, aggregates, and related materials.
  • Take necessary precautions to avoid damage to precast elements during storage, handling, and transport.

Breaking Strength Testing Frequency (Clause 2.1.2):

Handling Process Summary:

flowchart TD
    MaterialArrival[Material Arrival] --> Storage[Store on Firm Ground]
    Storage --> Supports[Place Temporary Supports at Designated Points]
    Supports --> Lifting[Lift with Care]
    Lifting --> Transport[Transport with Supports]
    Transport --> Placement[Place Without Damage]

References:

• IS 6061 Part 1 (1971)
• IS 4082-1967 (Storage Guidelines)

Following these steps helps maintain material integrity and structural performance.

Guidelines for Installing Floors or Roofs with Joists and Hollow Blocks (IS 6061 Part 1)

Essential Components (Clause 2.1.1):

• Precast reinforced or prestressed concrete joists spaced as per design.
• Hollow cement concrete filler blocks positioned between joists.
• Nominally reinforced RCC topping cast in place.
• Floor or roof finishing materials (e.g., tiles, terrazzo).
• Optional ceiling finishes beneath joists and blocks.

Important Specifications:

• Storage and handling of materials per IS 4082-1967.
• Joist spacing typically ranges from 450 mm to 600 mm center-to-center, based on load and span.
• RCC topping thickness generally 40–50 mm with reinforcement mesh.

Approved Floor Finishes (Clause 7.1.1):

Typical Floor Cross-Section:

graph TD
    CeilingFinish[Optional Ceiling Finish] --> HollowBlocks[Precast Hollow Blocks]
    HollowBlocks --> Joists[Precast Concrete Joists]
    Joists --> RCCDecking[Structural RCC Topping]
    RCCDecking --> FloorFinish[Floor Finishing Material]

Summary:

• Employ precast joists, hollow blocks, and RCC topping for lightweight and cost-effective flooring.
• Adhere to IS standards for handling, joist spacing, topping thickness, and finish selection.
• Choose floor finishing per IS 6061 Part 1 Table 7.1.1 for durability and appearance.

Summary of Floor Finishing Standards (IS 6061 Part 1, 1971 Edition)

Applicable IS Codes for Various Floor Finishes (Clause 7.1.1)

Concrete Topping and Base Preparation (Clauses 7.1 & 4.1)

• Structural topping cast with M-200 grade concrete (approx. 1:1.5:3 mix).
• Supporting structural elements must be level and thoroughly cured.
• A 75 mm thick leveling bed of plain concrete (1:2:4 mix) may be provided over load-bearing walls.
• Planning for service pipes and conduits should be completed before floor installation.

Typical Concrete Leveling Bed Mix:

Floor Finish Layer Diagram:

graph TD
    SupportStructure[Supporting Structure] --> ConcreteBed[Concrete Leveling Bed (75 mm, 1:2:4)]
    ConcreteBed --> StructuralTopping[Concrete Topping (M-200 Grade)]
    StructuralTopping --> FloorFinish[Floor Finish per IS Codes]
    FloorFinish --> FinalSurface[Final Floor Surface]

Recommendations:

• Follow detailed laying and finishing methods specified in respective IS codes.
• Ensure proper curing of concrete leveling bed and topping before applying finishes.
• Consider waterproofing as per IS 1346, IS 3036, or IS 4365.

Specifications and Design Guidance for Precast Reinforced/Prestressed Concrete Joists (IS 6061 Part 1)

• Maximum Span:

  • Up to 6 meters (Clause 2.2.2).

• Joist Depth:

  • For spans up to 4.2 m: 150 mm.
  • For spans from 4.2 m to 6 m: 200 mm (Clause A-1.1).

• Joist Width: Uniform width along length (Clause A-1.1).

• Design Standards:

  • Reinforced concrete joists: Design as per IS 456:1964.
  • Prestressed concrete joists: Design following IS 1343:1960 (Clauses 2.2.3, A-3.1).

• Reinforcement Details:

  • Follow IS 456 for reinforced and IS 1343 for prestressed joists (Clause A-3.1).
  • Fabrication details available in Appendix A (Clause 3.5).

Depth vs Span Reference Table

Design Considerations

• Employ flexural design principles from IS 456/IS 1343.
• Ensure appropriate prestressing or reinforcement to resist bending.
• Verify deflection and crack width limits per applicable codes.

flowchart LR
    SpanUnder4_2[Span ≤ 4.2 m] --> Depth150[Depth = 150 mm]
    Span4_2to6[Span 4.2 - 6 m] --> Depth200[Depth = 200 mm]
    DesignProcess[Design] --> JoistType{Joist Type}
    JoistType --> Reinforced[Reinforced - IS 456:1964]
    JoistType --> Prestressed[Prestressed - IS 1343:1960]
    Reinforcement --> Reinforced & Prestressed

For comprehensive reinforcement and prestressing layouts, consult Appendix A of IS 6061 Part 1.

Specifications for Precast Hollow Cement Concrete Filler Blocks (IS 6061 Part 1)

Requirements (Clause 3.6 & Appendix B):

• Blocks must comply with dimensional and strength criteria outlined in Appendix B.
• Typical block design for 600 mm joist center spacing shown in Fig. 2.
• Reinforcement is mandatory for spans equal to or exceeding 750 mm between joists.

Dimensions & Features (Fig. 2):

• Designed for 600 mm joist spacing.
• Hollow cores reduce weight and enhance thermal insulation.
• Typical dimensions approximately 230 mm width × 100 mm height × 450 mm length (verify exact sizes in Fig. 2).

Strength Testing (Clause B-2, Table B-2):

• Minimum testing: two blocks per batch or two per 1000 blocks.
• Minimum compressive strength around 3.5 MPa (refer to Table B-2).
• Blocks must maintain specified dimensional tolerances.

Reinforcement (Clause 1.5):

• For spans ≥ 750 mm, internal reinforcement should be provided inside hollow cores.
• Reinforcement improves load capacity and reduces cracking risk.

Summary Table:

flowchart LR
    HollowBlock[Precast Hollow Block] --> JoistSpacing{Joist Spacing}
    JoistSpacing -->|< 750 mm| NoReinforcement[No Reinforcement Needed]
    JoistSpacing -->|≥ 750 mm| ReinforcementNeeded[Provide Reinforcement]
    HollowBlock --> StrengthTesting[Breaking Strength Test]
    StrengthTesting --> TestSamples{Test 2 blocks per batch or per 1000}
    TestSamples --> PassCriteria[Pass if ≥ 3.5 MPa]

Refer to Appendix B and Fig. 2 of IS 6061 Part 1 for exact dimensions and reinforcement specifications.