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Recommendations of RILEM TC 178-TMC: 'Testing and modelling chloride penetration in concrete' Analysis of water soluble chloride content in concrete



Title: Recommendations of RILEM TC 178-TMC: 'Testing and modelling chloride penetration in concrete'
Analysis of water soluble chloride content in concrete
Author(s): RILEM TC 178-TMC
Paper category : journal
Serial title: Materials and Structures
Abreviated Serial title: Mater. Struct.
ISSN: 1359-5997
Publisher: RILEM Publications SARL
Volume: 35
Issue: 253
Issue date: 2002-11-01
Publication year: 2002
Pages: 586 - 588
Total Pages: 3
Nb references: 8
Language: English


Abstract: As chloride ions in concrete are partially bound with the solid phases,only the so-called free chlorides are a risk of reinforcement corrosion.
However there are experimental difficulties of an accurate measurement of either bound and free chlorides due to:a)their relation is not constant as it evolves with time and temperature, b)there are no reliable analytical methods of quantification of bound chlorides.
For free chlorides,it is generally accepted that the squeezing of hardened pastes of concretes gives the best approximation to the chloride ionic concentration existing in capillary pores [1-5 ].
Due to the complexity of this technique,and to its difficulty to be applied to concrete samples,methods based on leaching have been tried [6,7 ].
The present recommendation is the result of a Round Robin Test on chloride analysis in concrete,carried out by the Technical Committee TC 178-TMC.
A total of 20 laboratories around the world have participated in this part of the RRT making a total of 37 determinations of free chlorides in triplicate specimens for three different chloride concentrations.
Two different methods of extraction of water soluble chlorides from the solid sample [6 ]and [7 ]were tested, taking as the target values those obtained by squeezing the powdered samples by applying high pressure.
It was also decided that other methods could also be used to the choice of each laboratory.
The complete recipes and all the results including the statistical analysis can be found in [8 ].
As a final result,the two methods proposed were considered to be a suitable reference for extracting water soluble chlorides.
However provided that the method given in [6 ]is easier to perform,it has been considered to take it as the reference method for extraction of free chlorides,and is the only one described in the present recommendation.
Experimental description of the leaching with alkaline water method can be found in [7 ].


Online publication: 2002-09-27
Classification: RILEM Technical Committees
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/13841


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