Observation of flexural cracks in loaded concrete beams using MRI

This paper describes apparatus that enables loading of a concrete beam reinforced with aramid fibre-reinforced plastic (AFRP) inside the magnet of a magnetic resonance imaging (MRI) scanner, and the subsequent measurement in three dimensions of the propagation of fractures within the concrete. These are then correlated with the internal structure of the concrete which had been previously determined by scanning the beam soon after casting. The particular requirements of the test frame for use within the scanner and the methods used to satisfy them are described in detail, as is the test procedure. It is shown that the resultant images can be visualised either as two-dimensional (2-D) slices, or as 3-D data sets; the images can also be post-processed to highlight the particular feature of interest.