Overview
ISO 1920-1:2004 - Testing of concrete - Part 1: Sampling of fresh concrete specifies standardized procedures for the sampling of fresh concrete. The standard defines how to obtain representative samples for testing fresh-concrete properties or for making test specimens used to determine hardened-concrete performance (for example, compressive strength). ISO 1920-1 is the first part of the ISO 1920 series on concrete testing.
Safety note: when handling fresh concrete or wet cement, avoid skin and eye contact (use gloves, footwear and eye protection) and wash exposed skin immediately.
Key topics and technical requirements
- Sampling types
- Composite sample: several increments taken uniformly through a batch or mass and thoroughly mixed - suitable for preparing strength specimens.
- Spot sample: one or more increments taken at a single point - not recommended for manufacturing strength specimens because it may not represent the batch.
- Definitions
- Clear definitions of batch, increment, composite sample and spot sample.
- Apparatus
- Use non-absorbent scoop(s) and containers, a thermometer (±1 °C) when required, and a moist cloth for dampening equipment.
- Sampling procedure
- Establish a sampling plan and take a sample at least 1.5× the estimated quantity required for testing.
- For composite samples, take increments uniformly distributed (at least three places), disregard the very first and last discharge from mixers/truck mixers, and, when sampling a stream or heap, represent full width/depth.
- Record date and time of sampling.
- Handling and transport
- Protect samples from contamination, moisture change, vibration and extreme temperature variations; consider time-dependent changes in fresh concrete properties.
- Temperature
- Measure sample temperature in the container when required.
- Reporting
- Sampling report must identify sample type, works, batch, element represented, ambient conditions, sampler name/signature, temperature, deviations, and a declaration of conformity.
- Quality control
- Annex A describes a repeatability/monitoring procedure using duplicate samples from 20 batches and gives calculations and acceptance criteria (sampling and testing errors normally ≤ 3%).
Applications and users
ISO 1920-1 is used by:
- Construction site engineers and foremen for routine quality control
- Concrete testing laboratories preparing specimens for hardened-concrete tests
- Ready-mix suppliers and batch plant operators to document deliveries
- Quality managers, site inspectors and certification bodies verifying sampling validity
Use cases include pre-test sampling for slump, air content, temperature, and making standard test specimens for later compressive-strength testing.
Related standards
ISO 1920 series:
- ISO 1920-2 - Properties of fresh concrete
- ISO 1920-3 - Making and curing test specimens
- ISO 1920-4 - Strength of hardened concrete
(See ISO 1920 series for additional methods on sampling, testing and non‑destructive evaluation.)
