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


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.