Methods of physical tests for hydraulic cement, Part 6: Determination of compressive strength of hydraulic cement (other than masonry cement)

IS 4031 Part 6 - Scope Overview

IS 4031 Part 6 covers methods of testing cement, specifically the standard procedures for determining physical properties like fineness, consistency, setting times, soundness, and compressive strength.

Key Specifications & Tables:

• Permissible Variation on Weights (Clause 5.6, Table 1):

• Mix Proportions & Mixing (Clause 6.1): Defines standard mix ratios for cement testing.

Summary:

• The scope includes standardized testing methods ensuring uniformity and accuracy in cement quality assessment.
• The weights used in testing must conform to the permissible variations to ensure precision.
• The code supports quality certification and standardization under BIS guidelines.

flowchart LR
    A[IS 4031 Part 6] --> B[Physical Tests on Cement]
    B --> C[Fineness]
    B --> D[Consistency]
    B --> E[Setting Times]
    B --> F[Soundness]
    B --> G[Compressive Strength]
    B --> H[Weight Calibration (Table 1)]

For detailed procedures and formulas, refer to the full IS 4031 Part 6 document.

IS 4031 Part 6: Sampling and Selection of Test Specimen

Key Points:

• Sampling (Clause 2.1):

  • Cement samples must be taken per IS 3535:1986 (Methods of Sampling Hydraulic Cement).
  • Samples should represent the entire batch and be thoroughly mixed before testing.

• Specimen Moulding (Clause 6.2):

  • Mortar cubes are prepared using a standard vibration machine for compaction.
  • Typical cube size: 70.6 mm × 70.6 mm × 70.6 mm (standard size for compressive strength tests).

• Testing Procedure:

  • Mortar mix ratio: usually 1 part cement : 3 parts standard sand by weight.
  • Water-cement ratio as specified in the relevant standard or mix design.
  • Compaction by vibration ensures uniform density and minimal voids.

Summary Table: Sampling & Specimen Preparation

flowchart TD
    A[Sample Cement per IS 3535] --> B[Mix Thoroughly]
    B --> C[Prepare Mortar (1:3 ratio)]
    C --> D[Fill Cube Mould (70.6 mm)]
    D --> E[Compact using Vibration Machine]
    E --> F[Cube Specimen Ready for Testing]

This ensures representative, uniform specimens for reliable compressive strength results.

IS 4031 Part 6: Temperature and Humidity Specifications for Cement Testing

• Moulding Room, Dry Materials & Water Temperature:
  Maintain at 27 ± 2°C (Clause 3.1, 6.1.1)

• Laboratory Relative Humidity:
  Maintain at 65 ± 5% (Clause 3.1)

• Moist Closet / Moist Room Conditions:
  Temperature: 27 ± 2°C
  Relative Humidity: ≥ 90% (Clause 3.2)

• Water Quality:
  Use potable or distilled water for mixing (Clause 6.1.1)

• Sampling:
  Follow IS 3535-1986 for cement sampling to ensure representativeness (Clause 2.1)

Summary Table

Notes:

• Maintaining these conditions ensures consistent hydration and curing of cement mortar cubes.
• Deviations can affect strength test results and repeatability.
• Use clean appliances and proper mixing techniques as per IS 4031 Part 6.

flowchart LR
    A[Sampling Cement] --> B[Maintain Temp 27±2°C]
    B --> C{Location}
    C --> D[Moulding Room]
    C --> E[Moist Room]
    D --> F[Humidity 65±5%]
    E --> G[Humidity ≥ 90%]
    B --> H[Water Temp 27±2°C]
    H --> I[Potable/Distilled Water]

This diagram shows the control points for temperature and humidity during cement testing.

IS 4031 (Part 6) - Standard Sand for Cement Testing

• Standard Sand: Must conform to IS 650-1966 (Specification for standard sand).
• Mix Proportions (Clause 6.1.2):

• P = Percentage of water for standard consistency (from IS 4031 Part 4).

• Mixing Procedure (Clause 6.1.3):

  • Dry mix cement + standard sand for 1 minute.
  • Add water and mix until uniform color (3-4 minutes max).
  • If mixing exceeds 4 minutes, discard and repeat.

• Standard Sand Properties (from IS 650-1966):

  • Clean, dry sand.
  • Particle size: 90% passing 600 micron sieve, retained on 150 micron sieve.
  • Free from clay, dust, and organic matter.

Summary Formula for Water Quantity:

[ \text{Water} = (P + 3)% \times (200g + 600g) = (P + 3)% \times 800g ]

This ensures consistent mortar strength testing per IS standards.

IS 4031 (Part 6) - Apparatus Specifications Summary

• Vibration Machine (Clause 5.1):
  Used for compacting cement mortar cubes. Must conform to IS 10080-1982.

• Standard Sand:
  As per Specification for standard sand for testing cement (first revision).

• Graduated Glass Cylinders (Clause 5.7):

  • Capacity: 150 to 200 ml
  • Permissible variation: ±1 ml
  • Graduation marks:
    • Main lines in circles, numbered
    • Least graduations extend ≥ 1/7 circumference
    • Intermediate graduations extend ≥ 1/5 circumference
    • No graduations for lowest 5 ml

• Mixing Conditions (Clause 6.1.1):

  • Clean appliances
  • Water and room temperature: 27 ± 2°C
  • Use potable or distilled water

Key Notes:

flowchart TD
    A[Vibration Machine] --> B[Compact Cement Mortar Cubes]
    C[Standard Sand] --> B
    D[Glass Cylinder] --> E[Measure Water Volume Accurately]
    F[Mixing Conditions] --> B

This ensures repeatability and accuracy in cement mortar testing per IS 4031 Part 6.

IS 4031 Part 6: Preparation of Test Specimens for Compressive Strength

Key Specifications for Moulding Specimens (Clause 6.2)

• Mix Proportions (Clause 6.1.2, Table 6.1):

• Where:
  • P = % water required for standard consistency (from IS 4031 Part 4)
  • Water quantity = (P + 3)% × (cement + sand mass)

Preparation Steps:

• Mix cement and sand separately for each cube.
• Add water as per above proportion.
• Mould specimens immediately after mixing.
• Compact specimens in 3 layers with 25 strokes per layer.
• Cure specimens in water until testing age.

Summary Formula for Water Content:

[ \text{Water} = \left(P + 3\right)% \times (200 + 600) \text{ g} ]

flowchart TD
    A[Measure Cement 200g] --> B[Measure Sand 600g]
    B --> C[Calculate Water: (P + 3)% of 800g]
    C --> D[Mix Cement + Sand + Water]
    D --> E[Mould Specimen in 3 Layers]
    E --> F[Compact Each Layer with 25 Strokes]
    F --> G[Cure Specimen until Test Age]

This ensures standardized, reproducible specimens for compressive strength testing per IS 4031 Part 6.

IS 4031 Part 6: Testing Procedure for Hydraulic Cement

Key Specifications & Apparatus:

• Standard Sand: Use as per IS 10080-1982 for testing cement.
• Vibration Machine: Required for compacting mortar specimens (Clause 5.1).

Specimen Preparation:

• Moulding Specimens (Clause 6.2):
  • Use standard moulds (typically 70.6 mm cubes).
  • Mix cement and standard sand in specified proportions.
  • Compact mortar in mould using vibration machine to avoid voids.

Calculation (Clause 8.1):

• Strength is calculated as:

[ \text{Compressive Strength} = \frac{\text{Load at Failure (N)}}{\text{Cross-sectional Area (mm}^2)} ]

• Cross-sectional area for 70.6 mm cube = (70.6 \times 70.6 = 4984 \text{ mm}^2).

Testing Procedure Summary:

1. Prepare mortar with cement and standard sand.
2. Fill moulds and compact by vibration.
3. Cure specimens as per IS 4031 Part 2.
4. Test specimens for compressive strength at specified ages (e.g., 3, 7, 28 days).
5. Calculate strength using above formula.

flowchart TD
    A[Prepare Cement + Standard Sand] --> B[Mix to Mortar]
    B --> C[Fill Moulds]
    C --> D[Compact using Vibration Machine]
    D --> E[Cure Specimens]
    E --> F[Compression Test]
    F --> G[Calculate Strength]

This ensures uniformity and repeatability in cement strength testing per IS 4031 Part 6.

IS 4031 Part 6 - Key Formulas, Tables & Specifications for Calculation

1. Mix Proportions (Clause 6.1.2)

• Cement: 200 g
• Standard Sand: 600 g
• Water: (P + 3.0)% of combined mass of cement + sand
  • P = water % for standard consistency (from IS 4031 Part 4)

2. Permissible Variation on Weights (Clause 5.6, Table 1)

3. Calculation Notes

• Water content is adjusted based on standard consistency to ensure proper mix.
• Weighing accuracy is critical; use weights within permissible variation.

flowchart TD
    A[Cement: 200g] --> C[Mixing]
    B[Standard Sand: 600g] --> C
    C --> D[Add Water: (P + 3)% of (Cement + Sand)]
    D --> E[Mix thoroughly]
    E --> F[Cast Cubes for Testing]

Summary: Use precise weights per Table 1, mix cement, sand, and water as per Clause 6.1.2, adjusting water for standard consistency. This ensures reliable compressive strength testing.

IS 4031 Part 6: Curing of Concrete Specimens

Key Specifications for Curing (Clause 6.3)

• Initial moist curing: Keep filled moulds in a moist closet/room for 24 hours after vibration.
• Post-mould curing: Remove specimens from moulds and immediately submerge in clean fresh water.
• Water renewal: Change water every 7 days.
• Temperature: Maintain water temperature at 27 ± 2°C.
• Prevent drying: Specimens must not dry out before testing.

Environmental Conditions (Clause 3.1)

• Moulding room temperature: 27 ± 2°C
• Relative humidity: 65 ± 5%

Testing (Clause 7.1)

• Test 3 cubes for compressive strength at each specified curing age.
• Curing period starts from completion of vibration.

Summary Table for Curing Conditions

flowchart TD
    A[Fill and Vibrate Moulds] --> B[Moist Closet for 24h]
    B --> C[Remove from Moulds]
    C --> D[Submerge in Water @ 27±2°C]
    D --> E[Renew Water every 7 days]
    E --> F[Keep Specimens Moist until Testing]
    F --> G[Test 3 Cubes per Period]

This ensures standardized curing for accurate compressive strength results.

IS 4031 (Part 6) - Acceptance Criteria for Compressive Strength of Hydraulic Cement

Key Points:

• This part specifies methods to determine compressive strength of hydraulic cement (other than masonry cement).
• Acceptance criteria are based on compressive strength values obtained from standard test specimens.
• Final test results should be rounded off as per IS 2-1960 to the same decimal places as specified values.

Relevant Formula for Compressive Strength:

[ f_c = \frac{P}{A} ]

• (f_c) = compressive strength (N/mm²)
• (P) = maximum load applied (N)
• (A) = cross-sectional area of specimen (mm²)

Permissible Variation on Weights (Clause 5.6 - Table 1):

Summary:

• Use standard specimen size and test method as per IS 4031 Part 6.
• Calculate compressive strength using the load and specimen area.
• Compare results with specified strength values after rounding.
• Ensure weights used in testing conform to permissible variations for accuracy.

flowchart LR
    A[Prepare Cement Specimens] --> B[Apply Load in Compression Testing Machine]
    B --> C[Record Maximum Load (P)]
    C --> D[Calculate Compressive Strength \(f_c = P/A\)]
    D --> E{Is \(f_c\) ≥ Specified Strength?}
    E -- Yes --> F[Accept Cement Batch]
    E -- No --> G[Reject Cement Batch]

This ensures cement meets strength criteria for structural safety.

IS 4031 Part 6: Amendments and Revisions Summary

Amendments & Revisions Overview:

• Amendment No. 1: (Date not specified) - Included in Fourth Reprint, Feb 2006.
• Amendment No. 2 (March 2002):
  • Clause 5.4 updated: Gauging trowel to conform to IS 10086:1982.
  • Footnote added for mould specifications in cement/concrete testing.
  • Clause 6.3 timing changed from "24 hours" to "24 ± 1 hours".
• Amendment No. 3 (Feb 2003): Minor editorial updates in Part 6.

Key Specifications from Amendments

Notes on Amendments & Revisions Process:

• BIS holds copyright; reproduction requires permission.
• Amendments reflect updates in testing procedures or equipment standards.
• Regular review ensures harmonization with current practices.

flowchart LR
    A[Original IS 4031 Part 6] --> B[Amendment No. 1]
    B --> C[Amendment No. 2 (Mar 2002)]
    C --> D[Amendment No. 3 (Feb 2003)]
    D --> E[Fourth Reprint (Feb 2006)]

For detailed test procedures, consult the latest IS 4031 Part 6 document and related referenced standards like IS 10086.