How many increments are required to form a composite sample?

A minimum of 3 well-distributed increments should be taken from the batch.

What is the minimum volume of concrete required for a standard sample?

Typically 20 litres, or at least 150% of the volume required for the specific tests to be conducted.

Can I take a sample from the very first discharge of the transit mixer?

No, samples should be taken from the middle portion of the batch, actively ignoring the first and last portions of the discharge to ensure representative sampling.

IS 1199 Part 1

: 1986

Methods of sampling and analysis of concrete - Part 1: Sampling of fresh concrete

CurrentEssentialTesting MethodMaterials Science · Testing Methods and Quality Control

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This standard specifies the procedures for obtaining representative samples of fresh concrete from stationary mixers, transit mixers, or at the site of pouring. It provides the foundational procedure for QA/QC engineers to ensure that subsequent workability and strength tests accurately reflect the concrete batch properties.

Covers the procedure for obtaining representative samples of fresh concrete from mixers or during placing.

Quick Reference Values

minimum increments for composite sample3 increments

minimum sample volume20 Litres (or 1.5 times the required test volume)

maximum time for sampling15 minutes

ignored discharge volumeFirst and last 10-15% of the batch

Practical Notes

Always remix the sampled concrete on a non-absorbent surface using a shovel before testing to eliminate any segregation that occurred during sampling or transport.

Never sample from the very beginning or the very end of a mixer discharge; these portions are often not representative of the main batch.