Characterisation of fibres distribution in a steel fibre reinforced concrete with electrical resistivity measurements

Steel fibre reinforced concrete (SFRC) is a new material allowing innovative projects for concrete structures. Such structures are designed using assumptions on the material fabric. Checking these assumptions requires, according to recommendations, coring and mechanical testing of samples. Non-destructive assessment, if validated, would provide an interesting alternative, making the checking process easier, quicker and less expensive.Blind tests in laboratory compare electrical resistivity measurements obtained with a four-probes square device, to visual analysis during pouring. After having defined a measurement process, the representativity of electrical resistivity values is assessed by analysis of measurements on eight slabs. Electrical resistivity allows the identification of a high or low resistivity axis, which gives the local orientation of steel fibres. The calculation of electrical anisotropy gives an indication of the “intensity of fibres orientation” in each area. In this article, the complete analysis process is detailed on two slabs which have been casted according to two different fibres distributions. These tests confirm the ability of electrical resistivity method to provide data on steel fibres within concrete, via a non-destructive way.