How many TMT bar samples do I need to test for a 40-tonne truck?

For a lot up to 100 tonnes, you need 2 samples per 25 tonnes. For 40 tonnes, this means taking 4 samples (2 for the first 25t, 2 for the remaining 15t). Refer to Table 1 for details.

What is considered a 'lot' of steel?

A lot is a collection of bars of the same size, grade, and from the same cast/heat, submitted for inspection at one time. As per Clause 3.1, the maximum mass of a lot is 100 tonnes.

What happens if one sample fails its strength test?

If a test piece fails, the sample is considered defective. Since Table 1 typically allows for 0 defective samples, the lot is considered non-conforming. However, Clause 6.2 provides a re-test procedure where additional tests can be done to potentially accept the lot.

IS 10790

: 2000

Methods of sampling of steel for prestressed and reinforced concrete, Part 2: Reinforcing steel

CurrentFrequently UsedTesting MethodMaterials Science · Concrete Reinforcement (Steel)

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This standard specifies the methods for sampling reinforcing steel from a given lot or batch for conducting quality control tests. It defines the lot size, the number of samples to be drawn based on the lot size, and the acceptance criteria for the lot based on test results. It is the primary standard used for quality assurance of reinforcement steel at manufacturing plants and construction sites.

Methods of sampling of steel for prestressed and reinforced concrete, Part 2: Reinforcing steel

Quick Reference Values

Maximum Lot Size100 tonnes

Sample Size (Lot ≤ 100 t)2 samples per 25 tonnes or part thereof

Sample Size (Lot 101-300 t)3 samples per 50 tonnes or part thereof

Permissible Defective Samples (Mechanical Tests, Typical)0

Number of test pieces per sample for tensile test1

Number of test pieces per sample for bend/rebend test1

Practical Notes

This code tells you 'how many' samples to take and 'acceptance criteria'. The actual test procedures are in other codes like IS 1608 (for tensile testing) and IS 1599 (for bend tests).

The acceptance criteria in Table 1 is '0' defectives for most sample sizes, meaning a single sample failure leads to the rejection of the entire lot, subject to retest provisions in Clause 6.

Ensure proper tagging and identification of samples from the point of collection to the laboratory to maintain traceability to the original lot.