Development of muon scattering tomography for a detection of reinforcement in concrete

Abstract

Inspection of ageing, reinforced concrete structures is a world-wide challenge. Existing non-destructive evaluation techniques in civil and structural engineering have limited penetration depth and don’t allow to precisely ascertain the configuration of reinforcement within large concrete objects. The big challenge for critical infrastructure (bridges, dams, dry docks, nuclear bioshields etc.) is understanding the internal condition of the concrete and steel, not just the location of the reinforcement. In most new constructions the location should be known and recorded in the as-built drawings, where these might not exist due to poor record keeping for older structures. Muon scattering tomography is a non-destructive and non-invasive technique which shows great promise for high-depth 3D concrete imaging. Previously, we have demonstrated that individual bars with a diameter of 33.7 ± 7.3 mm can be located using muon scattering tomography. Here we present an improved method that exploits the periodicity of bar structures. With this new method, reinforcement with bars down to 6 mm thickness can be detected and imaged.

Development of muon scattering tomography for detection of reinforcement in concrete

“…The double layer, i.e. with 0 cm separation, leads to a much higher signal as expected, see [1], where the signal is shown as a function of the rebar diameter for a single layer. As the incoming angles are small and the resolution of the detectors are finite, the scattering vertices are well defined in the horizontal plane but there is large uncertainty in the vertical direction.…”

“…The peak locations are determined by the mesh size. The presence of these peaks proves the presence of the rebar mesh and provide the mesh spacing, rebar diameter and location of the rebars, see [1].…”

“…For details on the method, please see [1]. For each muon that traverses the test volume, the incoming and outgoing tracks are reconstructed.…”

“…Muon tomography is a novel, non-destructive imaging technique, which allows for imaging the interior structure of large objects. In [1] a method for the precise estimation of the rebar size based on muon tomography was presented. Using only one week worth of data taking, bars with a diameter of 7 mm and larger, could easily be detected for a 10 cm spacing.…”