The image to the left is from a BFI concrete petrographer's report. The image is the surface of a core sample taken from a distressed concrete warehouse slab. The surface exhibits various types of surface defects. Embedded wood materials were found in the slab, along with other debris. Imprints of polymer fibers were also found on the surface of the slab. Dark spots were also visible on the surface of this concrete warehouse slab.
Below is an excerpt from the report that provides details that are characteristic of a concrete petrography report:
"Most of the hairline cracking and crazing is typical of shrinkage. This cracking is mostly surficial in nature and does not penetrate significantly into the concrete. However, some of the hairline cracking is associated with aggregate shadowing. Some examples of hairline cracks were observed that form circular patterns that trace the outline of aggregate particles immediately subjacent to the finished surface. Other examples were observed where trellis-like hairline crack patterns were observed above near-surface aggregate particles. In these cases the hairline cracking is from shrinkage associated with rapid drying of the paste over near-surface aggregate particles; this is ultimately related to aggregate shadowing."
There is great value in having an experienced concrete consultant team investigate a distressed concrete warehouse slab. If you are an attorney representing a developer, contractor, subcontractor, or insurance company involved in a construction defect dispute involving a distressed concrete warehouse slab please consider Building Forensics International and their experienced team of concrete consultants and petrographers.