AS 1012.20.2:2016 Methods of testing concrete
9 OTHER QUANTITATIVE METHODS (VOLHARD TITRATION)
The test solution prepared as in Clause 8.1 shall be used for determination of chloride content by a Volhard titration method that has been shown by calibration on reference solutions of sodium chloride to meet the requirements set out below. One suitable method is the EN 1744-1 ‘Test for the chemical properties of aggregates- Determination of water-soluble chloride salts using the V olhard method’.
Chloride content shall be expressed as a percentage C1- (by mass) of the oven-dry sample, using the calculation formulas given in the selected method. Any Volhard titration method may be used, provided that the analytical accuracy of the method is demonstrated and recorded as follows:
(a) Using aliquots of standard solutions described in Clause 8.2.4.
(b) Determining the repeatability standard deviation for duplicate analyses of the standard solutions, determined by the same operator at the same time using the same equipment.
NOTE: EN 1744-1 quotes a formula for repeatability for the Volhard titration by which the value at 0.2% chloride would be 0.0062%, and at 0.4% would be 0.012%. Therefore the values of the duplicate tests should not vary by more than 0.017% and 0.034%, respectively.
10 RECORDS
The following information concerning each sample shall be recorded:
(a) Identification of sample.
(b) Details of location of sampling including any special sampling techniques employed.
(c) Date of testing and name of analyst.
(d) Details of reference solutions Date and location of record of confirmatory method test results.
(e) Chloride content Method of determination used, mass of sample, volume of aliquot and calculated chloride content in percentage to the nearest 0.001%.
11 REPORT
The following information shall be reported:
(a) Identification of sample.
(b) Details of location of sampling including any special sampling techniques employed.
(c) Date of testing.
(d) Chloride content Method of determination used and calculated chloride content as a percentage to the nearest 0.001%.
(e) Such other information contained in the records as may be requested.
(f) The number of this Standard (i.e. AS 1012.20.2).