Title:
Effects of Environmental Exposure on the Performance of Cast-In-Place and Retrofit Anchors in Concrete
Author(s):
Christopher C. Higgins and Richard E. Klingner
Publication:
Structural Journal
Volume:
95
Issue:
5
Appears on pages(s):
506-517
Keywords:
adhesive; anchorage; anchors (fasteners); concretes; environments;
expansion anchors; service life;
DOI:
10.14359/565
Date:
9/1/1998
Abstract:
In this study, single cast-in-place anchors and retrofit anchors (expansion, undercut, and adhesive) were exposed to five simulated environmental exposure conditions: 1) ultraviolet light; 2) freezing and thawing; 3) corrosion in a pH-neutral salt solution; 4) wetting and drying with simulated acid rain; and 5) combined freezing and thawing, corrosion in a pH-neutral salt solution, and wetting and drying. To evaluate the effects of different environmental exposures, the tensile load-deflection behavior of the exposed anchors was compared with that of otherwise identical unexposed anchors. Ultraviolet light exposure did not affect the anchors studied. Freeze-thaw exposure reduced the preload and decreased the initial stiffness of torque-controlled expansion anchors. Salt (corrosion) exposure did not adversely affect the behavior of expansion anchors. Wetting and drying exposure to simulated acid rain did not significantly affect the anchors studied. The combination exposure reduced the stiffness of some torque- controlled expansion anchors. These results show that when expansion anchors are used in concrete subjected to cycles of freezing and thawing, their preload should be checked regularly. The results also imply that in concrete subject to cycles of freezing and thawing while wet, water should be prevented from entering the drilled holes of mechanical anchors.