Title: Quantifying Conservativeness of Water-Soluble Chloride Testing

Author(s): Ahmed A. Ahmed and David Trejo

Publication: Materials Journal

Volume: 120

Issue: 2

Appears on pages(s): 13-24

Keywords: admixed chlorides; bound chlorides; carbonation; chloride release; chloride testing; specialty cements

DOI: 10.14359/51738499

Date: 3/1/2023

Abstract:
Proponents of water-soluble chloride testing argue that only chlorides in the pore solution contribute to corrosion and that this testing is more representative of free chlorides and therefore should be required. Proponents of acid-soluble chloride testing argue that although water-soluble testing may be more representative of free chlorides in the pore solution at early ages, bound chlorides can become unbound with time, making the water-soluble test unconservative for predicting later-age free chlorides. However, watersoluble testing likely unbinds some admixed chlorides during testing. If the number of chlorides released as part of the watersoluble test exceeds the number of chlorides released at later ages (that is, from carbonation), the water-soluble test should be sufficiently conservative. This research quantifies the release of admixed chlorides as a result of testing and carbonation. Results indicate that water-soluble testing is sufficiently conservative in most cases for assessing admixed chloride contents in various cementitious systems.