Evaluation of Thermal Integrity Profiling and Crosshole Sonic Logging for Drilled Shafts with Concrete Defects

Thermal integrity profiling (TIP), which uses temperatures measured along drilled shafts during concrete curing to identify defects, has recently gained favor as an allowable concrete integrity test method for drilled shafts. Drilled shaft concrete temperatures are theoretically sensitive to defects anywhere within the shaft, which presents an opportunity for improving detection over the widely used crosshole sonic logging (CSL) method. This paper describes investigations conducted to compare detectability from TIP and CSL measurements for various types of defects. TIP and CLS measurements are presented for three full-scale drilled shafts constructed with ten intentional defects varying in location, character, and size. Comparison of these measurements indicates TIP and CSL tests are generally complementary with regard to their detection abilities. Each test method is effective for identifying certain types of defects, but limited or incapable of identifying other types of defects. The paper also includes an evaluation of the role of time on the detectability of TIP interpretations, demonstrating that the temperature effect of defects generally peaks around the time of the maximum rate of temperature rise and decreases significantly thereafter.