Methods of physical tests for hydraulic cement, Part 10: Determination of drying shrinkage

IS 4031 Part 10: Introduction - Key Formulas, Tables, and Specifications

1. Drying Shrinkage Calculation (Clause 9.1):
After measuring specimen lengths at 7 and 35 days, calculate drying shrinkage as:

[ \text{Drying Shrinkage (%)} = \frac{\Delta L}{L_0} \times 100 ]

• (\Delta L) = Average difference in length of 3 specimens (to nearest 0.01%)
• (L_0) = Effective gauge length

2. Permissible Variations on Weights (Clause 4.2, Table 1):

3. Rounding Off (Clause 0.4):
Final test values must be rounded off as per IS 2-1960, retaining the same significant figures as specified.

4. Accessories:
Flow table and accessories must conform to IS 5512-1969 (Clause 4.5).

flowchart TD
    A[Measure Specimen Lengths at 7 and 35 days]
    B[Calculate Average Length Difference (ΔL)]
    C[Calculate Drying Shrinkage % = (ΔL / L0) × 100]
    A --> B --> C

This summarizes the introductory essentials for testing cement drying shrinkage per IS 4031 Part 10.

IS 4031 Part 10 - Scope Summary & Key Specifications

Scope:
This part of IS 4031 specifies the methods for measurement of length change (drying shrinkage) of hardened cement paste, mortar, and concrete.

Key Specifications & Procedures

• Test Temperature:

  • Initial & subsequent measurements at 27 ± 2°C
  • Specimens stored at 27 ± 2°C and 50 ± 5% RH

• Specimen Handling:

  • Protect from moisture loss before initial length measurement
  • Use length comparator for measurement
  • Maintain same specimen orientation during measurements

• Flow Table & Accessories:

  • Conform to IS 5512

Important Formula (Clause 9.1)

Calculate drying shrinkage (%) as:

[ \text{Drying Shrinkage} = \frac{\Delta L}{L_0} \times 100 ]

Where:

• (\Delta L) = Average length change of 3 specimens (mm)
• (L_0) = Effective gauge length (mm)

Report to nearest 0.01%.

Summary Table

flowchart TB
    A[Prepare Specimens] --> B[Store at 27±2°C, 50±5% RH]
    B --> C[Measure Initial Length (L0)]
    C --> D[Store Specimens]
    D --> E[Measure Length at 7 & 35 Days (L)]
    E --> F[Calculate Drying Shrinkage %]

Note: Follow IS 2-1960 for rounding off values to match specified significant figures.

IS 4031 Part 10: Sampling & Selection of Test Specimens for Drying Shrinkage

Key Points:

• Specimen Type: Rectangular specimens prepared under controlled conditions.
• Batch Mixing: Mix materials separately per batch using proportions from Clause 6.2; water quantity per IS 4031 Part 7 to achieve flow 100-115% (25 drops in 15 sec).
• Mechanical Mixing: As per IS 4031 Part 7, Clause 7.3.1.
• Number of Specimens: Test at least three specimens per batch.
• Measurement Ages: Length measured at 7 days and 35 days.
• Drying Shrinkage Calculation:

[ \text{Drying Shrinkage (%)} = \frac{\text{Average length difference at 7 and 35 days}}{\text{Effective gauge length}} \times 100 ]

• Report average difference to the nearest 0.01%.

Summary Table: Drying Shrinkage Calculation

flowchart TD
    A[Batch Mixing] --> B[Prepare 3 Specimens]
    B --> C[Measure Length at 7 Days]
    C --> D[Measure Length at 35 Days]
    D --> E[Calculate Avg. Length Difference]
    E --> F[Calculate Drying Shrinkage %]
    F --> G[Report Result]

This ensures standardized sampling and accurate drying shrinkage determination per IS 4031 Part 10.

IS 4031 Part 10: Temperature and Humidity Requirements

Key Points:

• Temperature control is critical at 27 ± 2°C for all curing, drying, and moulding processes.
• Relative humidity varies by process:
  • Moist curing: ≥90%
  • Drying cabinet: 50 ± 5%
  • Moulding room: 65 ± 5%
• Humidity and temperature must be measured at least twice daily in drying cabinets.
• Uniform circulation of conditioned air in drying cabinets ensures consistent evaporation rates.

flowchart LR
    A[Moist Room] -->|27±2°C, RH≥90%| B[Curing of Specimens]
    C[Control Cabinet] -->|27±2°C, RH=50±5%| D[Drying of Specimens]
    E[Moulding Room] -->|27±2°C, RH=65±5%| F[Preparation of Moulds]

Maintaining these conditions ensures reliable and consistent test results per IS 4031 Part 10.

IS 4031 Part 10 - Apparatus and Equipment Specifications Summary

Key Apparatus Specifications:

• Flow Table & Accessories: Must conform to IS 5512-1969 for hydraulic cements and pozzolanic materials.
• Length Comparator: Used for measuring length change of hardened cement paste, mortar, and concrete specimens.
• Specimen Storage: Control cabinet at 27 ± 2°C and 50 ± 5% RH to avoid moisture loss.
• Measurement Temperature: Specimens, comparator, and reference bar at 27 ± 2°C during length measurements.

Important Formulas & Calculations (Clause 9.1):

Drying Shrinkage (%) after 7 and 35 days:

[ \text{Drying Shrinkage} = \frac{\Delta L}{L_0} \times 100 ]

• (\Delta L) = Average length difference of 3 specimens (mm)
• (L_0) = Effective gauge length (mm)
• Report to nearest 0.01%

Measurement Procedure (Clause 8.2):

• Initial length measured after removal from water.
• Protect specimens from moisture loss before initial reading.
• Final length measured after 28 days under controlled conditions.
• Specimens placed in comparator with same orientation as initial measurement.

Rounding Off Results:

• Follow IS 2-1960 for rounding off test results.
• Retain significant digits equal to specified values.

flowchart TD
    A[Prepare Specimens] --> B[Store at 27±2°C & 50±5% RH]
    B --> C[Initial Length Measurement]
    C --> D[Store for 28 days]
    D --> E[Final Length Measurement]
    E --> F[Calculate Drying Shrinkage]

For detailed apparatus dimensions and tolerances, refer to IS 5512-1969 and related IS codes mentioned.

IS 4031 Part 10: Preparation of Moulds - Key Points

1. Mould Specifications

• Beam mould size: 25 mm × 25 mm cross-section, 282 mm internal length (per IS 10086-1982).
• Moulds must be thinly coated with mineral oil before use.
• Stainless steel or non-corroding metal reference inserts with knurl heads are set to get an effective gauge length of 250 mm.
• Inserts must be clean and oil-free.

2. Material Preparation & Mixing (Clause 6.3)

• Dry materials mixed separately per proportions in Clause 6.2.
• Water quantity as per IS 4031 Part 7 (7.2.1 & 7.3) to achieve a flow of 100-115% with 25 drops in 15 seconds.
• Mechanical mixing as per IS 4031 Part 7 (7.3.1).

3. Environmental Conditions (Clause 3.1)

• Temperature: 27 ± 2°C for moulding room, materials, and water.
• Relative humidity: 65 ± 5%.

Summary Table:

flowchart TD
    A[Dry Materials] --> B[Mix with Water]
    B --> C[Mechanical Mixing]
    C --> D[Prepare Moulds]
    D --> E[Coat Mould with Mineral Oil]
    E --> F[Insert Reference Inserts (250 mm gauge)]
    F --> G[Cast Specimens]

This ensures consistent, reproducible test specimens as per IS 4031 Part 10.

IS 4031 Part 10: Preparation of Mortar - Key Points

Materials & Proportions (Clause 6.2)

• Cement : Standard Sand = 1 : 3 by mass
• Sand: Standard sand as per IS 650.

Mixing Conditions (Clause 6.1)

• Use clean appliances.
• Water and room temperature: 27 ± 2℃.
• Use potable or distilled water.

Mould Preparation (Clause 5.1)

• Moulds thinly coated with mineral oil.
• Stainless steel/non-corroding metal inserts with knurl heads for 250 mm gauge length.

Moulding Procedure (Clause 7.1)

• Mix thoroughly, mould in two layers.
• Compact each layer by pressing with thumbs and forefingers.
• Ensure mortar fills corners, around inserts, and mould surfaces.
• Level and smooth top layer with a trowel.
• Use rubber gloves during handling.

Summary Table: Mortar Mix and Conditions

flowchart TD
    A[Materials: Cement + Standard Sand (1:3)] --> B[Mixing with Water at 27±2℃]
    B --> C[Mould Preparation: Mineral Oil Coated Mould + Inserts]
    C --> D[Moulding: Two Layers, Compact by Hand]
    D --> E[Level & Smooth Surface]
    E --> F[Test Specimen Ready for Testing]

This ensures uniform, reproducible mortar specimens for strength testing as per IS 4031 Part 10.

Key Specifications and Procedures for Moulding Specimens (IS 4031 Part 10):

• Mixing Proportions (Clause 6.3):

  • Use dry materials as per proportions in Clause 6.2.
  • Water quantity per IS 4031 Part 7 (Clauses 7.2.1 & 7.3) to achieve a flow of 100-115% with 25 drops in 15 seconds (flow table test).
  • Mechanical mixing as per IS 4031 Part 7, Clause 7.3.1.

• Mould Dimensions (Clause 4.6):

  • Beam mould size: 25 mm x 25 mm cross-section.
  • Internal length: 282 mm (conforming to IS 10086-1982).
  • Effective gauge length between reference inserts: 250 mm.

• Environmental Conditions (Clause 3.1):

  • Temperature: 27 ± 2°C for moulding room, dry materials, and water.
  • Relative humidity: 65 ± 5%.

• Mould Preparation (Clause 5.1):

  • Thinly coat moulds with mineral oil to prevent adhesion.
  • Insert stainless steel/non-corroding metal reference inserts with knurl heads for gauge length.

Summary Table

flowchart TD
    A[Dry Materials] --> B[Mixing with Water]
    B --> C[Mechanical Mixing (IS 4031 Pt 7)]
    C --> D[M

IS 4031 Part 10: Procedure of Testing (Key Points & Formulas)

1. Specimen Preparation & Moulding (Clause 6.3):

• Mix dry materials separately per proportions in Clause 6.2.
• Water quantity per IS 4031 Part 7 (7.2.1 & 7.3) to achieve flow 100-115% with 25 drops in 15 seconds.
• Mechanical mixing as per IS 4031 Part 7 (7.3.1).

2. Length Measurement (Clause 8.2):

• Initial length measured immediately after removal from water using a length comparator.
• Specimens and comparator at 27 ± 2°C.
• Protect specimens from moisture loss before initial reading.
• Store specimens at 27 ± 2°C and 50 ± 5% RH.
• Measure length again after 28 days under same temperature conditions.
• Specimens placed in comparator with same orientation as initial measurement.

3. Rounding Off Results (Clause 0.4):

• Round off final test values as per IS 2-1960.
• Retain the same number of significant figures as specified in the standard.

Typical Length Change Calculation

[ \text{Length Change (%)} = \frac{L_{28} - L_0}{L_0} \times 100 ]

• (L_0) = Initial length
• (L_{28}) = Length after 28 days

Summary Table: Environmental Conditions for Testing

flowchart TD
    A[Mix Materials] --> B[Measure Flow (100-115%)]
    B --> C[Mould Specimens]
    C --> D[Store at 27±2°C, 50±5% RH]
    D --> E[Initial Length Measurement]
    E --> F[Store for 28 Days]
    F --> G[Final Length Measurement]
    G --> H[Calculate Length Change %]

IS 4031 Part 10: Drying Shrinkage Calculation

Key Formula (Clause 9.1)

Drying shrinkage (%) is calculated as:

[ \text{Drying Shrinkage} = \frac{\Delta L}{L_0} \times 100 ]

Where:

• (\Delta L = L_7 - L_{35}) = Average difference in length between 7 days and 35 days specimens (in mm)
• (L_0) = Effective gauge length of specimen (in mm)

Procedure Summary:

• Measure length of 3 specimens at 7 and 35 days.
• Calculate average length difference to nearest 0.01% of gauge length.
• Report this as drying shrinkage.

Specifications:

• Specimens: Rectangular, prepared as per IS 4031 Part 10.
• Testing conditions: Controlled humidity and temperature as per standard.
• Gauge length: Precisely measured for accuracy.

Practical Notes:

• Use micrometer or length comparator for precise measurement.
• Ensure specimens are cured and dried under specified conditions.
• Average over 3 specimens improves reliability.

flowchart TD
    A[Prepare 3 Specimens] --> B[Measure Length at 7 Days (L7)]
    B --> C[Measure Length at 35 Days (L35)]
    C --> D[Calculate ΔL = L7 - L35]
    D --> E[Calculate Drying Shrinkage % = (ΔL / L0) × 100]
    E --> F[Report Average Shrinkage]

This method ensures consistent evaluation of cement drying shrinkage per IS 4031 Part 10.

Reporting of Results as per IS 4031 Part 10

Key Points:

• Rounding Off Results (Clause 0.4):
  Final test values must be rounded according to IS 2-1960, retaining the same number of significant digits as the specified standard value.

• Drying Shrinkage Calculation (Clause 9.1):
  Calculate the average length change of three specimens at 7 and 35 days:
  [ \text{Drying Shrinkage} = \frac{\sum (\Delta L)}{3 \times L_0} \times 100 % ]
  where:

  • (\Delta L) = change in length of each specimen (mm)
  • (L_0) = effective gauge length (mm)
    Report to the nearest 0.01%.

• Measurement Conditions (Clause 8.2):

  • Initial and subsequent length measurements at 27 ± 2°C.
  • Specimens stored at 27 ± 2°C and 50 ± 5% RH.
  • Use length comparator; ensure consistent specimen orientation.

Permissible Variation on Weights (Table 1, Clause 4.2)

Summary Diagram of Reporting Process

flowchart TD
    A[Measure Initial Length at 27±2°C] --> B[Store Specimens at 27±2°C, 50±5% RH]
    B --> C[Measure Length at 7 and 35 Days]
    C --> D[Calculate Average Shrinkage %]
    D --> E[Round off as