Thermal Integrity Profiling is a technology that utilizes the heat generated by curing of concrete to assess the integrity and quality of drilled shafts, augered cast in place (ACIP) piles and other concrete foundations. From the test results, necks, bulges, variations in concrete cover and the as-built shape of the shaft, including steel cage eccentricities, can be characterized.
Drilled shafts and ACIP piles are prepared for Thermal Integrity Profiling during their construction, by the installation of Thermal Wire® Cables or access tubes. GRL engineers perform this test using a Thermal Integrity Profiler.
When shafts are equipped with Thermal Wire cables, temperatures are automatically sampled throughout the concrete hydration process starting immediately after casting. GRL Engineers typically retrieve the data for analysis and reporting after 12 to 48 hours depending upon shaft diameter and mix design.
An average temperature at a certain depth that is significantly lower than the average temperatures at other depths potentially indicates a concrete deficiency or defect. If records at certain depth shows regions with cooler temperatures (when compared to the average temperature at that depth), a local concrete deficiency or local defect may be present.
The GRL engineer interprets the collected TIP data and prepares a report that typically includes graphical displays of measured temperatures versus depth, indicating the overall average concrete temperature, unusually hot or cold spots, and variations in temperature at each depth. When information on concrete volume is known, the report may also include an estimate of the effective shaft radius and the cage alignment or offset from center.
Thermal Integrity Profiling is standardized by ASTM D7949 – Standard Test Methods for Thermal Integrity Profiling of Concrete Deep Foundations.