Corrosion in Precast Concrete
FPrimeC was engaged by the client to conduct corrosion assessment of precast concrete elements (hollow core balcony slabs and precast stairs) of an existing hotel structure in Thornbury, ON. The precast concrete elements showed sign of extensive corrosion, severe cracks, and delamination which raised concerns regarding the structural integrity and adequacy of these critical elements.
Nondestructive Evaluation of Corrosion
FPrimeC designed and performed a Non-Destructive Evaluation program to evaluate the extent and severity of corrosion. The purpose of this evaluation was to advise the client of a practical timeline if/when a repair-replacement procedure should take place.
Visual Inspection
Digital visual inspection was conduced to create 3D live models of existing deterioration. The images were used to determine the extent of existing defects, such as cracking, delamination, and spalling. FPrimeC adapted an advanced LiDAR solution which allowed for accurate location based defect assessment.
Half-Cell Corrosion Potential Mapping (HCP)
Half-Cell Corrosion Potential (HCP) survey was performed to assess the likelihood of corrosion at different locations. The procedure was based and adapted from the ASTM C876 standard for the collection of field measurements as well as the interpretation of the test results. A systematic grid was adopted to take measurements which were conducted with reference to a single origin point. The data collected was formulated into a tricolor heat map to represent the likelihood of corrosion in certain areas of the component. The test allowed FPrimeC engineers evaluate the extent and severity of corrosion in the precast concrete elements.
Corrosion Rate Measurement
Corrosion Rate Measurement was performed at select test locations to assess the rate of cross section loss. This method measures the corrosion rate of steel in concrete by the “polarization resistance”. This is a nondestructive technique that allowed FPrimeC to better estimate how fast corrosion was growing, and provide necessary evidence to base a repair timeline for the owner.
