Q

Are there known Thermal Integrity Profiler (TIP) testing results that show voids in the shaft? If so, how well are the voids represented?

A

Yes, there are TIP results that clearly show voids in the shaft. In his paper, written for the DFI Journal, Prof. Gray Mullins from the University of South Florida described a test on a drilled shaft with intentionally built defects. Please click on the following link to access the paper:

 Mullins, G., December, 2010. Thermal Integrity Profiler of Drilled Shafts. DFI Journal Vol 4. No. 2 December 2010: Hawthorne, NJ; 54-64

In the paper, the case history and caption for Figure 9 are of special interest. The defects shown in Figure 9 are clear and logical because no heat was present in the defect. The normal hot temperature signature of the shaft was interrupted by the “cold defect,” which is indicative of a void or weak concrete quality. In other words, defects are shown as local cool spots.