FPrimeC Solutions Inc. has been engaged by Rio-Tinto Alcan to perform visual inspection and nondestructive evaluation of Concrete Silo at Rio-Tinto facility in Kitimat, BC. The concrete silo showed sign of delamination on the surface. The main objective of the project was to evaluate the present condition of the concrete silo following the preliminary visual inspection. The nondestructive testing of concrete silo structure was performed on the exterior face of the silo structure.
1- Visual Inspection
Visual condition of concrete at select locations on the exterior of the silo was examined where safe access was possible. A light metal hammer was used to assess potential delamination and major integrity issues on the surface.
2- Nondestructive Evaluation of Concrete Silo
Ground Penetrating Radar (GPR) was used to identify the location, and distribution of steel bars. Where applicable, GPR maps were calibrated to estimate the depth of steel bars. GPR line scan was used to locate vertical and horizontal reinforcement in the concrete silo wall.
A combination of Ultrasonic Pulse Velocity (UPV), and Rebound (Schmidt) Hammer tests was used to assess quality and uniformity of concrete. Ultrasonic Pulse Velocity (UPV) was used to verify the pulse velocity in concrete, and assess concrete quality and uniformity at select areas. Rebound Hammer test was used to assess uniformity and surface hardness of the concrete.
Impact-Echo test method (ACI 228.2R-13 and ASTM C 1383) was used to verify the wall thickness in different locations of the silo.