Title: Efficacy of Ultrasonic Pulse Velocity Testing to Assess Sulfate-Degraded Concrete

Author(s): Julie Ann Hartell, Andrew J. Boyd, and Patrice Rivard

Publication: Symposium Paper

Volume: 317

Issue:

Appears on pages(s): 1-16

Keywords: Durability, sulfate attack, ultrasonic pulse velocity, condition assessment.

DOI: 10.14359/51700847

Date: 6/1/2017

Abstract:
The phenomena involving hydrated cement paste and a source of sulfate anion have been extensively studied over the last four decades. The present publication provides an overview of past external sulfate attack studies along with current views on the accuracy of standard methods to evaluate the performance of a concrete mixture in service; illustrating the need to find other means of laboratory testing based on “real” exposure conditions representative of sulfate reaction kinetics encountered in field structures. This study evaluates the efficacy of stresswave propagation testing to detect concrete microstructural disparities related to sulfate-induced damage. While respecting traditional means of inducing an external sulfate attack in the laboratory (complete immersion in a 5% sodium sulfate solution), the experimental study proposed a different methodology for evaluating the extent of sulfate degraded concrete in the laboratory. Over a 2-year exposure term, the extent of degradation of various specimen types, replicating transport mechanisms reminiscent of those seen in the field, were evaluated using ultrasonic pulse velocity. Through statistical analysis, the results discussed demonstrated that the test procedures conducted were reliable for assessing the changes in behaviour observed.