Q

Have there been results from testing with the Thermal Integrity Profiler (TIP) that show voids in the shaft and if so how well were they represented?

A

The answer is Yes, and they are very clearly shown. In a paper written for the DFI Journal ( Mullins, G., December, 2010. Thermal Integrity Profiler of Drilled Shafts. DFI Journal Vol 4. No. 2 December 2010: Hawthorne, NJ; 54-64), Prof. Gray Mullins of the University of South Florida describes such a test on a drilled shaft with purposely-built defects. The case history and text commenting on Figure 9 in that paper are of special interest. The defects are very clear, and that is very logical since there is no heat produced in the defect. The normal hot temperature signature of the shaft is interrupted by the “cold defect” (which can be a void, or even very weak concrete quality), so the defect shows as a local cool spot.