GB/T 24175-2009Test method for stability of steel slag (English PDF)

Foreword

GB/T 24175-2009 was issued on 25 June 2009 by the General Administration of Quality Supervision, Inspection and Quarantine and the Standardization Administration of the People's Republic of China, and has been in force since 1 April 2010. It is classified under ICS 77.140.99 and CCS H 54.

The document is a recommended national standard: the /T in the designation marks it as recommended rather than compulsory, which in the Chinese system means it is the method the reviewer applies.

1 Scope

China's national test method for the stability of steel slag. Steel slag is produced in enormous quantity - roughly a tenth of a tonne for every tonne of steel - and using it as aggregate in road base and concrete is the only route that consumes it at that scale. The obstacle is a specific and destructive one: the slag contains free calcium and magnesium oxide left unreacted from the lime added in refining, and those hydrate slowly when wet, expanding as they do. The expansion is delayed by months or years, so a road built on unstable slag looks perfect and then heaves, and concrete made with it cracks from within. That single failure mode is why slag must be aged in stockpiles or steam-treated before use, and why a test is needed to establish whether a given slag is stable. The standard specifies the terms and definitions, the apparatus, the determination of the immersion expansion ratio, the determination of the autoclave chalked ratio, and the test report.

This standard specifies the terms and definitions, the instruments and apparatus, the determination of the immersion expansion ratio, the determination of the autoclave chalked ratio, and the test report for the test methods for the stability of steel slag.

The method for determining the immersion expansion ratio applies to steel slag used as road subgrade and base course material, steel slag used as aggregate for asphalt pavement, and steel slag used as engineering backfill. The autoclave chalked ratio method applies to steel slag used in building mortar, in building material products and in concrete.

2 Normative references

The following documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) or revisions do not apply; however, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions. For undated references, the latest edition applies.

GB/T 750 Test method for autoclave soundness of portland cement

GB/T 6003.1 Test sieves - Technical requirements and testing - Part 1: Test sieves of metal wire cloth

GB/T 6003.2 Test sieves - Technical requirements and testing - Part 2: Test sieves of perforated metal plate

GB/T 8170 Rules of rounding off for numerical values

GB/T 50123 Standard for soil test method

3 Terms and definitions

The terms and definitions given in YB/T 804 and the following apply to this standard.

3.1 immersion expansion ratio - the rate of volume change of steel slag after immersion under the specified test conditions.

3.2 autoclave chalked ratio - the proportion by mass of particles smaller than 1.18 mm after the steel slag has been chalked under the specified conditions of pressure and time.