ISO 1920-1:2004

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.)