Green concrete: Embracing change

The detection of the first Brazilian field case of the thaumasite form of sulfate attack (TSA) was studied. As part of the investigation, the visual aspect of the damaged concrete was recorded. In order to preserve the actual conditions of the damage at the time it was discovered, the samples taken were wrapped in cling film and stored prior to tests. The mineralogy of the deteriorated products was determined by X-ray diffraction (XRD) and infrared spectroscopy (IRS). The attack was characterized by the formation of a white material, which replaced the original cement matrix. This material did not have any cohesiveness, thereby leaving the aggregate exposed. Typical features of TSA were seen in several sections of the beam, namely the formation of a white non-cohesive material at the expense of the hydrated cement matrix with the exposure of the aggregate, which could be easily detached from the bulk concrete.