Code of practice for laying of in-situ granolithic concrete floor topping

IS 5491: Scope and Key Specifications

• Scope: IS 5491 covers specifications for aggregates used in concrete, aligning with international standards and Indian field practices.

• Rounding Off (Clause 0.5): Test results must be rounded per IS 2-1960, retaining the same number of significant digits as specified values.

• Aggregates Grading (Clause 3.2.1.2): Fine aggregates are classified into two grading zones with specific sieve passing percentages:

This table guides the selection of fine aggregates based on particle size distribution for concrete mix design.

flowchart LR
    A[IS 5491 Scope] --> B[Aggregate Specifications]
    B --> C[Fine Aggregate Grading]
    C --> D[Grading Zone 1]
    C --> E[Grading Zone 2]
    D --> F[Sieve Sizes & % Passing]
    E --> F

Use this grading to ensure aggregate suitability for concrete quality and durability.

IS 5491: Definitions & Key Specifications

• Reference for Definitions:
  Clause 2.0 states that definitions are as per IS 2571-1963 and additional ones in IS 5491.

• Fine Aggregate Grading (Clause 3.2.1.2, Table 2):

• Rounding Off (Clause 0.5):
  Test results must be rounded per IS 2-1960, maintaining the same significant figures as specified values.

Summary:

• Use IS 2571 for definitions.
• Fine aggregate grading zones specify particle size distribution limits.
• Follow IS 2 for rounding off test values to ensure compliance.

flowchart TD
    A[IS 5491 Definitions] --> B[Refer IS 2571]
    A --> C[Fine Aggregate Grading]
    C --> D[Zone 1 & Zone 2 % Passing]
    A --> E[Rounding off per IS 2-1960]

This ensures standardization and uniformity in material specifications.

IS 5491: Key Material Specifications & Tables

1. Surface Hardening Solutions (Clause 3.6)

• Solutions include sodium silicate, magnesium silicofluoride, zinc silicofluoride, or proprietary blends.
• Proprietary materials must follow manufacturer's instructions (see Appendix A).

2. Water Quality (Clause 3.3)

• Use clean water free from oil, acid, alkali, organic/vegetable matter.
• Sea water is prohibited.
• Generally, potable water is suitable.

3. Aggregates

a) Coarse Aggregate Grading (Clause 3.2.1.1, Table 1)

b) Fine Aggregate Grading (Clause 3.2.1.2, Table 2)

4. References to Cement Specifications

• Ordinary, rapid hardening, low heat Portland cement (revised)
• Portland blast furnace slag cement (revised)
• Portland pozzolana cement (revised)

This ensures material quality and gradation essential for grano-lithic concrete floor topping as per IS 5491.

IS 5491: Design Considerations – Key Points

1. Surface Hardening Solutions (Clause 3.6)

• Use solutions like sodium silicate, magnesium silicofluoride, or zinc silicofluoride.
• Proprietary materials must follow manufacturer's instructions (see Appendix A).

2. Fine Aggregate Grading (Clause 3.2.1.2, Table 2)

3. Rounding Off (Clause 0.5)

• Test results must be rounded per IS 2-1960.
• Retain the same number of significant digits as the specified value.

This ensures consistency in surface treatment, aggregate grading for concrete mix design, and precision in test reporting.

IS 5491 - Compacting Plant: Key Specifications & Tables

1. Types of Compacting Plant (Clause 5.1)

• Hand tamper: Steel strip edge 75 mm wide, fixed with countersunk screws.
• Vibrating hand tamper: Electric or engine-driven vibrating units attached.
• Pneumatic tamper: Pneumatic hammers acting on steel plate.
• Pan vibrator: Used for uniform compaction.

2. Aggregate Grading for Floor Topping

3. Important Notes

• Tampers must compact the full thickness of each concrete layer.
• Surface finish quality depends on compactor type and operation.
• Damp-proofing of floors and walls up to 150 mm above base level is essential (Clause 4.5.1).

flowchart LR
    A[Concrete Layer] --> B[Compaction]
    B --> C{Type of Compactor}
    C --> D[Hand Tamper]
    C --> E[Vibrating Tamper]
    C --> F[Pneumatic Tam

IS 5491: Key Specifications for Laying Floor Topping Over Base Concrete

Surface Preparation (Clause 6.2)

• Clean base concrete thoroughly (remove dirt, laitance, loose particles).
• Roughen surface by wire brushing or hacking if hardened.
• Wet surface for several hours; mop off excess water before laying topping.
• Brush neat cement slurry on base concrete before topping.

Screed Strips

• Fix screed strips dividing base into panels (see Clause 4.2).
• Align joints in topping with base concrete joints.

Granolithic Concrete Mix

• Mix ratio: 1:1:2 (Cement : Sand : Stone aggregate).
• Lay topping, tamp thoroughly, strike off level.
• Float surface with wooden float.
• Check flatness with straightedge and spirit level; rectify immediately.
• Finish surface as per IS: 2571-1963.

Thickness & Types of Floor Topping (Table 3 Summary)

Additional Notes

• Monolithic topping contributes structurally to suspended slabs.
• Lime concrete cushioning (40-50 mm thick) should be tamped and leveled; clean surface before topping.
• If lime/bricks unavailable, 1:4:8 cement concrete may substitute cushioning.

Summary Formula for Granolithic Concrete Mix:

[ \text{Granolithic Concrete Mix} = 1 \text{ (Cement)} : 1 \text{ (Sand)} : 2 \text{ (Stone Aggregate)} ]

flowchart TD
    A[Prepare Base Concrete Surface] --> B

IS 5491: Key Specifications for Laying Floor Topping on Suspended Slabs

Important Procedures:

• Monolithic Method (Clause 7.1):

  • Structural concrete placed to finished thickness minus topping.
  • Surface roughened, laitance removed while green.
  • Topping (Granolithic 1:1:2) placed immediately after slab stiffens.
  • Topping compacted, screeded, floated with wooden float.
  • Contributes structurally to slab strength.

• Separate Topping (Clause 7.2):

  • Hardened slab surface cleaned, roughened by wire brushing/chipping.
  • Surface wetted, excess water removed.
  • Neat cement slurry brushed before topping.
  • Topping laid in panels with screed strips, compacted, leveled, floated.

Mix Proportion:

• Granolithic Concrete: Cement : Sand : Stone aggregate = 1 : 1 : 2

flowchart TD
    A[Structural Concrete of Suspended Slab] -->|Stiffens (green)| B[Monolithic Granolithic Topping (20mm)]
    A -->|Hardens| C[Surface Preparation: Roughen & Clean]
    C --> D[Apply Cement Slurry]
    D --> E[Separate Granolithic Topping (40mm)]
    A --> F[Cushioning Lime Concrete Layer (40-50mm)]
    F --> E

Summary:

• For monolithic topping, place topping immediately after slab stiffens (20 mm thick).
• For separate topping, roughen slab, apply slurry, and lay 40 mm topping.
• Cushion

IS 5491: Curing and Protection of Flooring

Key Specifications (Clauses 8.1 & 9.1)

• Immediate Protection: After finishing, protect the surface from rapid drying by shielding against wind, draught, and strong sunlight.
• Curing Duration: Keep the surface continuously moist for at least 10 days.
• Methods of Curing:
  • Wet gunny bags
  • 50 mm thick damp sand layer
  • Pooling water on the surface
• Traffic Restriction: No traffic allowed during curing to prevent surface damage.
• Inspection Points:
  • Base preparation (if flooring laid separately)
  • Proper compaction
  • Correct finishing
  • Correct curing

Notes on Admixtures & Surface Hardeners (Clauses 3.4 & 3.6)

• Admixtures (hardeners/accelerators) are generally not required but may be used cautiously per manufacturer’s instructions.
• Surface hardening solutions include:
  • Sodium silicate
  • Magnesium silicofluoride
  • Zinc silicofluoride
• Proprietary materials must follow manufacturer’s guidelines (see Appendix A).

Summary Table for Curing Methods

flowchart TD
    A[Finished Flooring Surface] --> B[Protect from Wind, Sunlight]
    B --> C[Start Curing Immediately]
    C --> D{Choose Curing Method}
    D --> D1[Wet Gunny Bags]
    D --> D2[50 mm Damp Sand]
    D --> D3[Pooling Water]
    D1 --> E[Keep Moist for 10 Days]
    D2 --> E
    D3 --> E
    E --> F[No Traffic During Curing]
    F --> G[Inspect: Base, Compaction, Finishing, Curing]

This ensures durable, high-quality flooring with minimal surface defects.

IS 5491: Inspection - Key Points

IS 5491 does not explicitly provide detailed clauses on Inspection procedures or formulas. However, based on standard practice and IS code conventions:

Inspection Guidelines (General Practice)

• Sampling & Testing: Follow IS 2-1960 rounding rules for test results.
• Aggregate Grading: Use Table 2 (Clause 3.2.1.2) for fine aggregate grading zones to verify compliance.

Table: Fine Aggregate Grading (IS 5491, Clause 3.2.1.2)

Important Notes:

• Inspection involves verifying aggregate grading against these limits.
• Use IS 2-1960 for rounding off test results.
• Definitions and terms refer to IS 2571-1963.

Summary Diagram: Inspection Flow

flowchart TD
    A[Sample Collection] --> B[Aggregate Sieving]
    B --> C{Check % Passing}
    C -->|Within Limits| D[Pass Inspection]
    C -->|Outside Limits| E[Reject / Reprocess]
    D --> F[Record Results (Rounded per IS 2-1960)]

For detailed inspection methods, refer to related IS codes on aggregates and materials testing.

IS 5491: Maintenance of Granolithic Concrete Floors

Key Points from Clause 10 (Maintenance):

• Cleaning: Frequent washing with water is generally sufficient unless oil/grease spills occur.
• Grease Removal: Use sodium metasilicate, caustic soda, phosphates, or proprietary cleaners for grease stains.

Inspection Checklist (Clause 9.1):

• Base preparation (especially if floor finish is separate)
• Proper compaction
• Correct finishing
• Adequate curing

Fine Aggregate Grading (Appendix A, Clause 3.2.1.2):

Summary:

• Maintenance mainly involves regular washing; grease requires chemical cleaning.
• Inspection during and post-construction ensures durability.
• Aggregate grading controls surface quality and strength.

flowchart TD
    A[Start: Floor Construction] --> B[Prepare Base]
    B --> C[Proper Compaction]
    C --> D[Correct Finishing]
    D --> E[Correct Curing]
    E --> F[Maintenance]
    F --> G{Oil/Grease Present?}
    G -- No --> H[Frequent Water Washing]
    G -- Yes --> I[Use Chemical Cleaners]
    H --> J[Floor Maintained Clean]
    I --> J

This flow ensures long-lasting granolithic floor performance per IS 5491.

IS 5491: Surface Treatment to Granolithic Concrete Floor Topping

Key Specifications & Procedures

• Surface Preparation (Clause 6.2):

  • Clean base concrete surface thoroughly (remove dirt, laitance, loose particles) by scrubbing with coir/steel wire brush.
  • If surface is too hard, roughen by chipping/hacking.
  • Saturate surface with water for several hours, then mop off excess before topping.
  • Apply neat cement slurry brushed onto base before topping.

• Mix for Topping:

  • Granolithic concrete mix ratio: 1 : 1 : 2 (Cement : Sand : Aggregate).

• Laying & Finishing:

  • Lay topping, tamp thoroughly, strike off level.
  • Float surface with wooden float.
  • Check flatness with straightedge & spirit level; rectify immediately.
  • Finish surface smooth as per IS 2571-1963.

• Surface Hardening (Clause A-1.1):

  • Dusting reduced by applying surface hardening solutions (renew annually).
  • Surface must be clean, dry, and free of grease/oil before treatment.
  • Clean by scrubbing and washing; allow drying for absorption.

Summary Table: Surface Preparation & Treatment

flowchart TD
    A[Base Concrete Surface] --> B[Clean & Roughen]
    B --> C[Wet & Mop Excess Water]
    C --> D[Apply Cement Slurry]