Concrete is the most widely used construction material, and its quality directly influences the strength, durability, and long-term performance of any structure. To ensure consistent and reliable results, every stage—from sampling and workability assessment to cube casting, curing, and compressive strength testing—must follow standardised procedures. The Fresh Concrete Sampling procedure provides a clear, practical, and site-ready methodology for concrete sampling and testing in line with IS codes, supporting engineers, supervisors, and quality control teams in achieving accurate and compliant results.
- Workability (Slump / Slump Flow / VSI for SCC)
- Temperature
- Density and Air Content
- Preparation of test cubes for compressive strength
1. PURPOSE
This document defines the procedure for sampling and testing of fresh concrete, including slump measurement, cube preparation, curing, and compressive strength testing.
2. SCOPE OF WORK
This procedure covers:
- Sampling of fresh concrete
- Measurement of slump/slump flow
- Casting of test cubes
- Laboratory testing of concrete samples
It is applicable to all projects under (Project Name).
3. REFERENCES
- Project Technical Specifications
- IS 516 – Method of Tests for Strength of Concrete
- IS 1199 – Methods of Sampling and Analysis of Concrete
- ITP for Concrete Works
- Approved drawings and relevant documents
4. MATERIALS
- Concrete of various grades is used in structural works.
5. MATERIAL DELIVERY & STORAGE
Concrete will be delivered from the approved batching plant as per project requirements.
6. MANPOWER
- Project Engineer
- Site Engineer
- QC Engineer
- Lab Technician
- Helpers
7. PLANT & TOOLS
- Slump Cone & Tamping Rod
- Flow Table with Flow Mould (for SCC)
- Cube Moulds – 150 × 150 × 150 mm (IS 10086)
- Weighing Scale
- Cube Testing Machine (CTM)
- Vibrator / Vibrating Table
8. WORK PROCEDURE
8.1 Before Sampling
- Verify inspection clearance of the element to be concreted.
- Verify the concrete delivery note and batch sheet:
- Grade of concrete
- Dispatch time from the batching plant
- Mix design compliance
- All transit mixers must report at the designated sampling area.
8.2 Slump Measurement (IS 1199, Clause 5)
Steps include:
- Clean and moisten the slump cone.
- Place on a level, rigid, non-absorbent base plate.
- Fill in four equal layers.
- Tamp each layer with 25 strokes.
- Strike off the concrete level.
- Lift the cone steadily in 5–10 seconds.
- Measure slump immediately.
- Record values in the Concrete Pour Card.
8.3 Flow Test (For Self-Compacting Concrete)
Steps include:
- Clean and prepare the flow table and mould.
- Fill the mould in two equal layers, 25 strokes each.
- Remove mould vertically.
- Drop the table 15 times in 15 seconds.
- Measure the spread diameter at 6 points.
- Calculate flow. Flow, percent is calculated as spread diameter in cm – 25 / 2.5 x 100
8.4 Casting of Compression Test Specimens (Cubes)
- Collect samples as per IS 1199 / IS 456 frequency.
- Oil the interior of moulds lightly.
- Fill the moulds in three layers (approximately 5 cm each).
- Compact each layer with 35 strokes or by vibration.
- Finish the top surface smoothly.
- Insert identification slips and mark cubes clearly.
8.5 Storing & Curing
- Keep cubes under damp gunny bags for the first 24 ± 0.5 hours.
- After demoulding, cure in clean water at 27 ± 2°C until testing.
8.6 Testing of Cubes (IS 516)
- Wipe surface water and clean CTM bearing surfaces.
- Load applied continuously without shock.
- Record maximum load at failure.
- Note any unusual failure pattern.
8.7 Calculation of Results
Compressive Strength=Maximum LoadMean Cross-Sectional Area\text{Compressive Strength} = \frac{\text{Maximum Load}}{\text{Mean Cross-Sectional Area}}Compressive Strength=Mean Cross-Sectional AreaMaximum Load
- Test results to be taken at 7 days and 28 days.
- The average of three cubes represents the batch (variation not more than ±15%).
- Maintain records in the Cube Register.
9. QUALITY CONTROL
- Standard deviation to be calculated for each grade (min. 30 results).
- SD < 6 is generally acceptable for RMC.
- Maintain concrete pour cards, cube records, and identification logs.
10. ATTACHED FORMATS (FREE DOWNLOAD)
- Concrete Pour Card – RMC Deliveries
- Concrete Compressive Strength Register
- Cube Identification System
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