When can external rust on anchor bolts be indicative of problems?

External rust on anchor bolts can be indicative of problems particularly when there is evidence of deep pits. This is significant because deep pits can compromise the integrity of the steel. The presence of deep pitting suggests that corrosion has penetrated deeper than just the surface layer, which could lead to a reduction in the cross-sectional area of the bolts and ultimately affect their load-bearing capacity.

Furthermore, deep pits may also serve as sites for further corrosion, as moisture and harmful chemicals can accumulate in these localized areas, exacerbating the deterioration. Thus, identifying and addressing deep pits is crucial in maintaining the structural integrity of anchor bolts.

While flaking rust may indicate some corrosion, it is the depth of the pits that poses the most significant risk because it can lead to critical failures. Distorted bolts can suggest other related issues such as overloading or improper installation, but they do not directly indicate corrosion severity as deep pits do. Lastly, significant swelling may indicate underlying problems, but it does not provide a clear indication of the extent of corrosion encountered compared to the specific insight given by deep pits on rusted surfaces.