The thermal method, based on measuring the hydration temperatures of fresh concrete, is the latest one devoted to testing the integrity of bored cast in situ piles (drilled shafts).
Unlike other methods, it is claimed to cover the whole volume of the piles, both inside and outside of the rebar cage. The flaw detection capabilities of the method are still undecided, having been established by a small number of controlled site tests. This limitation places lots of unclarity as to the integrity of the results of this method.
In the linked article, there are several cases showing that thermal profiles can miss some quite large defects in deep pile foundations. The document describes a new numerical method that can simulate the thermal behavior of newly-cast piles of any shape and under any boundary conditions. The results of a few situations modeled prove that under worst-case scenarios, the thermal method is unable to establish the integrity of the pile skin and may even totally miss a complete discontinuity. It is shown that the method still requires extensive improvements to qualify as a dependable tool for testing the integrity of concrete piles. The image below presents such an example at 16 meters. To the full article/document Challenge the simulator! ... here.
