ACI Adhesive Anchor Installer Certification Practice Exam

Which failure mode is characterized by the failure of the concrete material around the anchor?

1. Steel failure

2. Concrete pryout failure

3. Adhesive failure

4. Pull-out failure

The correct answer is: Concrete pryout failure

Concrete pryout failure is characterized by the failure of the concrete material surrounding the anchor rather than the anchor itself. This mode of failure typically occurs when the forces acting on the anchor induce significant stress in the concrete, causing it to break or "pry out" around the anchor. This situation often arises in scenarios where the anchor is subjected to high tensile loads that exceed the concrete's ability to bear the load, leading to a cone-shaped failure around the anchor. In contrast, steel failure would concern a failure in the anchor or its components, while adhesive failure involves the adhesive bond failing, which is not related to the concrete structure. Pull-out failure refers to the anchor being pulled out of the concrete without causing significant damage to the surrounding concrete but relies on the adhesive holding properties rather than the integrity of the concrete itself.