Title:
Rapid, Accurate Method for Determining Water-Soluble chloride in concrete, Cement, Mortar, and Aggregate: Application to Quantitative Study of Chloride Ion Distribution in Aged Concrete
Author(s):
S. W. Bishara
Publication:
Materials Journal
Volume:
88
Issue:
3
Appears on pages(s):
265-270
Keywords:
aggregates; beams (supports); bridge decks; cements (chlorides); diffusion; hardened concretes; mortars (materials); raw materials; Materials Research
DOI:
10.14359/1874
Date:
5/1/1991
Abstract:
Presents a rapid, accurate method to determine chloride in hardened concrete and concrete raw materials. After boiling the powdered sample for 10 min, undissolved matter is filtered out, and the filtrate is acidified to a pH value of 3 before titration against standard mercury (II) solution, using diphenylcarbazone as an indicator. Sixty-nine runs on a chloride-containing concrete beam gave an average of 0.0568 percent chloride content; the minimum was 0.049 percent and the maximum 0.062 percent chloride. The average agrees favorably with 0.056 percent obtained following the AASHTO procedure but using boiling water for 10 min to extract the chloride. The precision, as determined by the standard deviation for 69 runs on the same sample, amounted to 0.0026 percent chloride, and the spread is 0.013 percent chloride.