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In the last 100 years concrete and steel have been the most common building materials, that is the reason why they constitute the core of the structures on which the architecture of the 20th’s century is based. Both materials present high resistance and durability but the recent collapse of Minardi Bridge in Italy shows that it is absolutely necessary to carry out real-time monitoring of the conservation status of concrete. In this sense, the building of the Agencia Impositiva Federal (A.F.I.P.) which is located in the city of Paran´a, built in the 70s, represents a clear example of brutalist architecture in Argentina. After 40 years of its construction and during remodelling tasks, serious problems in the concrete structures were discovered that forced the evacuation of the building. In order to develop an in situ monitoring system that allows the premature detection of structural problems in 20th’s century heritage buildings, it was implemented an innovative scheme based on digital holographic interferometry (DHI) which includes a semiconductor laser, optical fibre and and ah hoc plastic support made by 3D printing. This system was tested on concrete specimens sujected to dynamic loads in the range of 1 × 103 kg to 28 × 103 kg using an Amsler hydraulic press. Results, though preliminary, showed that it is possible to measure in situ the radial deformation of normalised cylindrical specimens under pressure loads and indicated that this low cost, novel DHI set up, could be applied in situ, as a preventive conservation method, to detect cracks and other defects in monumental concrete works.
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