Due to the early deterioration of pile cap foundations in residential buildings and bridges in the metropolitan region of Recife, several samples taken from a pile cap block of a residential building, built about ten years ago, were studied. The problem of the extensive cracking in the pile cap foundation had its origin in the delayed ettringite formation, possibly due to a high heat of hydration due to the concreting of the large volume of concrete. In this work, laboratory tests were performed to evaluate the transport properties of concrete samples, as well as their physical and chemical composition using advanced analyses. The tests performed in the experimental campaign were the apparent porosity, gas permeability, scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The presence of crystalline products of the alkali-aggregate reaction was proven through physical–chemical analyses, such as Raman spectroscopy and EDS. Moreover, the ettringite crystals were observed in XRD standards, SEM images and in the chemical composition of EDS. The porosity showed a high value (between 9 and 10%), as well as the concrete permeability (10–16 m2 and 10–15 m2), determining the negative influence of ISR on the transport properties. Therefore, the methods used have proven to be effective in understanding the problem encountered and have the potential to be used in the design and execution of pile cap blocks.