Combining Non-destructive and Destructive Techniques for Concrete Condition Assessment: Fid-Bau Portal

Combining Non-destructive and Destructive Techniques for Concrete Condition Assessment

Hossack, Ashlee / West, Mike

The corrosion of reinforcing steel is the leading cause of deterioration of concrete structures, costing owners billions of dollars in repair and rehabilitation each year. As our infrastructure continues to age and experience further deterioration, fast and reliable condition assessment techniques are required. Until recently, condition assessments were limited to visual reviews, soundings, and concrete core extraction. Although these techniques provide valuable insight into the conditions of structures, the scope of data collection is limited. Numerous non-destructive technologies are now available for concrete condition assessments. Without causing damage to the structure, these technologies allow us to develop a greater understanding of the condition of the reinforcement. More complete, in-depth condition assessments are developed when non-destructive techniques are used in combination with visual assessment and concrete core extraction. An example of such a combined technique was used to assess a bridge deck in Atlantic Canada. A ground-penetrating radar (GPR) survey was carried out, a visual review of the structure was conducted, and concrete cores were extracted from key locations. The GPR survey data was used to map the areas of the deck which were most (and least) likely to be experiencing active corrosion. Concrete cores were extracted, and chloride profiles were measured. The core data was in excellent agreement with the GPR map, thereby validating the GPR data. The GPR survey produced a data set of over 6000 measurements. By validating this data with twelve cores, the map of deteriorated areas could be refined to a much greater resolution than a map produced with cores and soundings alone. Furthermore, the data collection was much faster than traditional assessment techniques, decreasing the disruption to traffic. The cost and duration of repair is reduced drastically with this combination of techniques, compared to traditional techniques. Furthermore, the map of deterioration can be used for future planning purposes; locations with minor chloride infiltration are identified before corrosion begins; and the membrane can be repaired at a fraction of the cost of concrete rehabilitation. By improving assessment techniques, we can prolong the life of ageing infrastructure and target repair funds to those structures most in need.