Methods of sampling and analysis of concrete

IS 1199: Scope - Key Formulas, Tables, and Specifications

1. Scope Overview (Clause 2.0)

• Defines terminology and standardizes test methods for concrete workability, compacting factor, and slump tests.

2. Compacting Factor Test Apparatus Dimensions (Clause 5.2.2.1, Table & Fig. 2)

3. Cylindrical Measures for Coarse Aggregate (Clause 7.2.3, Table 7.2)

4. Calculations (Clause 7.5)

• Details procedures to compute workability parameters such as compacting factor, slump, and flow.
• Compacting Factor (CF) formula:

[ CF = \frac{\text{Weight of partially compacted concrete}}{\text{Weight of fully compacted concrete}} ]

flowchart TD
    A[Upper Hopper (

IS 1199: Key Definitions, Formulas, and Tables

1. Definitions (Clause 2.0)

• Standard terms related to concrete testing and measurements are defined for uniform understanding.
• Example: Compacting Factor, Workability, Slump, etc.

2. Compacting Factor Test Apparatus (Clause 5.2.2.1, Table & Fig. 2)

3. Cylindrical Measures for Coarse Aggregate (Clause 7.2.3, Table 7.2)

Additional Notes:

• Compacting Factor (CF) formula:

  [ CF = \frac{\text{Weight of partially compacted concrete}}{\text{Weight of fully compacted concrete}} ]

• These dimensions ensure standardized testing apparatus for consistent workability and aggregate testing.

flowchart TD
    A[Upper Hopper] --> B[Lower Hopper]
    B --> C[Cylinder]
    style A fill:#f9f,stroke:#333,stroke-width:2px

IS 1199: Sampling of Fresh Concrete – Key Points

• Sampling Method (Clause 7.3 & 5.2.3, 5.3.3, 5.1.3):

  • Obtain samples as per Clause 3 (standard method for sampling).
  • For concrete with aggregate > 38 mm, wet-sieve through a 1½ inch (38 mm) screen to exclude larger particles.
  • Mix sample uniformly with a shovel before molding specimens to avoid segregation.

• Transport & Handling:

  • Transport samples promptly to the testing site.
  • Mix during transport to maintain uniformity.

• Apparatus Dimensions:

  • Use compacting factor apparatus as per Table I (dimensions in cm) for aggregates ≤ 38 mm.

• Flow Test Mould:

  • Use mould as per Fig. 3 with specified slide clearance for flow tests.

Summary Table for Sampling Concrete with Large Aggregate

Sampling Flowchart (Mermaid.js)

flowchart TD
    A[Start Sampling] --> B{Aggregate size > 38 mm?}
    B -- Yes --> C[Wet sieve through 38 mm screen]
    B -- No --> D[Direct sampling as per Clause 3]
    C --> E[Mix sample uniformly]
    D --> E
    E --> F[Transport sample carefully]
    F --> G[Proceed to testing]

Note: Always follow IS 1199 Clause 3 for the detailed sampling procedure to ensure representative samples.

IS 1199: Preparation of Test Specimens – Key Points

1. Mould Specifications (Clause 5.1.2)

• Shape: Frustum of a cone
• Dimensions:

  Parameter	Value (cm)
  Bottom diameter	20
  Top diameter	10
  Height	30

2. Specimen Casting & Storage (Clause 10.3.1)

• Store specimens in moist air for 3 to 7 days.
• Fix two 6.5 mm diameter steel balls at center of each end using rapid hardening cement.
• After fixing, keep specimen moist for at least 24 hours.
• Then immerse in water at 24–30°C until 28 days or as specified.

3. Filling Procedure (Clause 5.3.4)

• Wet and clean mould surface before use.
• Fill mould in two layers (~half volume each).
• Rod each layer with 25 strokes using a 1.6 cm diameter, 61 cm long rod.
• Strokes must be uniformly distributed and penetrate underlying layer.

Summary Table: Specimen Preparation

flowchart TD
    A[Mould Preparation] --> B[Wet & Clean Mould]
    B --> C[Fill 1st Layer]
    C --> D[Rod 25 Strokes]
    D --> E[Fill 2nd Layer]
    E --> F[Rod 25 Strokes]
    F --> G[Store in Moist Air (3-7 days)]
    G --> H[Fix Steel Balls at Ends]
    H -->

IS 1199 - Tests for Workability (Clause 5.2.1, 5.4.4.1, Table II)

Key Concepts:

• Workability: Ease of concrete compaction without segregation (Clause 2.17).
• Applicable for aggregate max size ≤ 38 mm.
• More precise than slump test, especially for low workability concrete.

Vee-Bee Test:

• Measures time (in seconds or "degrees") for concrete to change from a conical to a cylindrical shape under vibration.
• Sensitive for stiff mixes that fail slump test.

Consistency Scale (Table II):

Relation between Slump (cm) and Vee-Bee Degrees:

• Slump decreases as Vee-Bee degrees increase.
• Useful for correlating slump test with Vee-Bee for low workability mixes.

Summary:

• Use Vee-Bee test for low workability concrete.
• Refer to Table II for interpreting Vee-Bee degrees.
• For normal workability, slump test is sufficient.
• Measure and record reinforcement position if coring (Clause 4.5.3).

flowchart LR
    A[Concrete Sample] --> B[Vee-Bee Test]
    B --> C{Vee-Bee Degrees}
    C -->|>20| D[Very Dry to Moist Earth]
    C -->|10-20| E[Dry]
    C -->|3-10| F[Plastic to Semi-fluid]
    C -->|<3

IS 1199: Analysis of Freshly Mixed Concrete — Key Points

1. Consistency & Workability (Clause 5.4.4.1, Table II & Fig. 7)

• Consistency Scale (Vee-Bee Degrees):

• Relation: Slump (cm) vs. Vee-Bee degrees is shown in Fig. 7 (graphical correlation).

2. Analysis Procedure (Clause 6.1.1 & 6.10)

• Sample concrete within 5 minutes of discharge.
• Store airtight if delay, analysis within 2 hours from water addition.
• Test aggregates for specific gravity, water absorption, sieve analysis.
• Report includes:
  • Sample ID, test date
  • Weights & proportions of constituents
  • Water-cement ratio
  • Remarks (e.g., aggregate moisture equilibrium)

3. Key Calculations (Clause 7.1)

Summary Diagram: Concrete Consistency Scale

graph LR
A[Moist

IS 1199 Key Formulas & Tables for Calculations and Proportions

1. Calculation of Proportions (Clause 6.8)

Weights of constituents in concrete sample:

[ \begin{align*} W_c &= w \times C_f \ W_f &= w \times F_f \ W_e &= \left[w - (W_c + W_f)\right] \times F_e \ W_w &= W - (W_c + W_f + W_e) \end{align*} ]

Where:

• (W_c, W_f, W_e, W_w) = weights of coarse aggregate, fine aggregate, cement, and water respectively
• (w) = weight of concrete in water
• (W) = weight of concrete in air
• (C_f, F_f, F_e) = correction factors based on specific gravities minus 1 for coarse aggregate, fine aggregate, and cement respectively

2. Constant R Calculation (Clause 8.3.4)

[ R = \frac{W \times 100}{w} ]

• (R) = volume of calibration cylinder as % of measuring bowl volume
• (W) = weight of concrete in air
• (w) = weight of concrete in water

3. Compacting Factor Test Dimensions (Clause 5.2.2.1)

flowchart LR
    A[Upper Hopper (A)]
    B[Lower Hopper (B)]
    C[C

IS 1199: Determination of Air Content in Concrete

Key Formulas

1. Air Content by Weight:

[ A = \frac{T - W}{T} \times 100 ]

• (A) = Air content (% by volume)
• (T) = Theoretical weight of concrete (kg/m³) on air-free basis
• (W) = Actual weight of concrete (kg/m³)

2. Air Content by Volume:

[ A = \frac{4 \times 100 \times (V - V_A)}{V} ]

• (V) = Volume of concrete produced per batch (m³)
• (V_A) = Total absolute volume of ingredients (m³)

3. Theoretical Weight Calculation:

[ T = \frac{W_i}{V_A} ]

• (W_i) = Weight of each ingredient (kg)
• (V_A) = Sum of absolute volumes = (\sum \frac{W_i}{\text{Specific Gravity}_i \times 1000}) (m³)

Aggregate Correction Factor (G)

• (G = h_1 - h_2) (difference in readings from aggregate tests)
• Corrects apparent air content (A_1) to actual air content:

[ A = A_1 - G ]

• Determined experimentally due to variability with aggregate type.

Procedure Summary (Clause 8.4)

• Place concrete in 3 layers in bowl; rod or vibrate each layer.
• Rod each layer with 25 strokes; tap bowl 10-15 times.
• Remove excess water/foam; ensure pressure-tight seal.
• Measure pressure and calculate air content.

Notes

• Use saturated surface-dry bulk specific gravity for aggregates.
• Re-check aggregate correction factor periodically.
• Pressure method suitable except for highly porous aggregates.

flowchart TD
    A[Sample Concrete] --> B[Place in Bowl (3 layers)]
    B --> C[Rodding/Vibration each layer]
    C --> D[Tap bowl to remove bubbles]
    D --> E[Strike off excess water/foam]
    E --> F[Seal bowl for pressure test]
    F --> G[Measure pressure]
    G --> H[Calculate apparent air content A1]
    H --> I[

IS 1199: Cement Content of Hardened Concrete - Key Points

1. Cement Content Determination (Clause 9.1)

• Applicable for hardened Portland cement concrete except when aggregates/admixtures liberate soluble silica (e.g., slags, diatomites).
• Cement content is determined by chemical analysis of hardened concrete samples.

2. Cement Content Calculation (Clause 7.1)

• Weight of fresh concrete per m³ is measured.
• Cement factor (C) = Cement content per m³ of concrete.
• Formula for cement content per m³:

[ C = \frac{\text{Weight of cement in batch (kg)}}{\text{Volume of concrete batch (m}^3)} ]

• Volume of concrete per batch is calculated from weight and density.

3. Specific Gravity of Cement (Clause 3.15)

• Use 3.15 as specific gravity unless measured otherwise.

4. Air Content Correction (Clause 8.3.8)

• Air content A (%) affects volume calculations.
• Apparent air content A1 and aggregate correction factor G (%) are used to correct volume.

Summary Table: Key Values

flowchart TD
    A[Fresh Concrete Batch] --> B[Measure Weight]
    B --> C[Calculate Volume (using density)]
    C --> D[Determine Cement Content (kg/m³)]
    D --> E[Apply Air Content & Aggregate Corrections]
    E --> F[Final Cement Content of Hardened Concrete]

Note: For precise cement content, chemical analysis of hardened concrete is essential per IS 1199 Clause 9.1.

IS 1199: Drying and Measurement of Specimens

Drying Oven Specifications (Clause 10.2.2)

• Internal volume: ≥ 0.008 m³ per specimen, minimum total 0.05 m³
• Air circulation: Fan for effective air movement
• Temperature: Maintained at 50 ± 1ºC
• Humidity control: ~17% RH using saturated calcium chloride solution
  • Exposed solution area ≥ 1 m² per m³ oven volume
  • Solid CaCl₂ must remain above solution surface during test

Drying & Measurement Procedure

• Drying duration: ≥ 44 hours at 50ºC and ~17% RH
• Cooling: ≥ 4 hours in desiccator with saturated CaCl₂
• Length measurement: At 24 to 30ºC with accuracy ±0.005 mm
• Temperature correction:
  [ L_{corrected} = L_{measured} \times \left(1 - 0.00002 \times \frac{T - 25}{2}\right) ] where (T) = measurement temperature in °C

Repeat Cycle (Clause 10.4.1)

• Repeat drying, cooling, measuring until length change < 0.01 mm for 15 cm specimen (proportional for larger sizes)
• No wet specimens placed during drying cycle
• Free air access to all specimen surfaces

Summary Table: Drying Oven & Measurement

flowchart TD
    A[Start: Wet Spec