- Author
-
Carino, N. J.
|
Sansalone, M.
- Title
- Detection of Voids in Grouted Ducts Using the Impact-Echo Method.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Journal
-
ACI Materials Journal,
Vol. 89,
No. 3,
296-303,
May/June 1992
- Report
-
Title 89-M34,
- Keywords
-
voids
|
grout
|
ducts
|
impact
|
concretes
|
nondestructive tests
|
post-tensioning
|
prestressing steels
|
reinforcing steels
|
stresses
|
walls
- Abstract
- The impact-echo method was used to detect simulated voids in grouted post-tensioning tendon ducts cast in a 1-m (39.4-in.) thick concrete wall specimen. The study was part of a program sponsored by CANMET to evaluate nondestructive test methods based on stress wave propagation. The locations of the voids in the ducts were not known by the authors until after their results had been reported to the principal investigator of the project. The impact-echo method successfully located most of the voids. The study provided impetus for additional experimental and analytical studies to gain a better understanding of the interaction of stress waves with voids in cylindrical ducts. It also highlighted the need to increase the speed of testing and to develop a method to automate signal interpretation.