Standards Development

Scope

This document specifies test methods applicable to prestressing steel (bar, wire or strand) for concrete. This document does not cover the sampling conditions that are dealt with in the product standards.

Purpose

The proposal is to introduce the distilled water test in the Clause 11. This test is another way to check the durability of the prestressing steels.

The distilled water test is representative of onsite environment contrary to NH4SCN test that prones massive hydrogen embrittlement

This test was found to be more severe than the ammonium thiocyanate test for some products especially for the high classes (2060 & 2160) of the small diameter strands (T5.2)

Since this survey, higher class (2360 MPa) products have appeared which have a “finer” metallurgy (microstructure, impurities, KIc, etc…) and a comparative evaluation of the results of the various corrosion tests is in progress

For France market, using this corrosion test (NF A05-302) in conjunction with ISO 15630-3 corrosion test provides an additional degree of confidence for end users.

This distilled water corrosion test is also introduced in the prEN10138-3, which is using 15630-3 in the normative reference.