ACI Adhesive Anchor Installer Certification Practice Exam

What factors have a more significant impact on adhesive bond strength than air temperature?

1. Sound and vibration levels

2. The condition of the concrete

3. Humidity and air pressure

4. Graphic identification codes

The correct answer is: The condition of the concrete

The condition of the concrete significantly impacts adhesive bond strength because the porosity, texture, and cleanliness of the concrete surface directly influence how well the adhesive can adhere. For instance, a surface that is clean, rough, and free of contaminants allows the adhesive to penetrate and bond more effectively, whereas a surface that is dirty, oily, or has previous coatings can hinder the bond, regardless of the air temperature. Other factors like humidity and air pressure, while they do play a role in the adhesive curing process, are generally secondary to the physical characteristics of the substrate. Likewise, sound and vibration levels can have an effect on the performance of adhesives in certain contexts, but they do not generally alter the intrinsic bond strength as much as the substrate condition does. Graphic identification codes are not relevant factors in determining adhesive bond strength. Therefore, the condition of the concrete is the most critical factor affecting adhesive bond strength beyond air temperature.