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Updated: Jul 25, 2025
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Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures
Published on: August 31, 2017
15.5K
Bridging the Gap: Assessing Material Performance of Laboratory Specimens and Concrete Structures.
Juan M Lozano-Valcarcel1, David Ov2, Thomas Kränkel1
1Chair of Materials Science and Testing, Centre for Building Materials, School of Engineering and Design, Technical University of Munich, 80333 Munich, Germany.
Materials (Basel, Switzerland)
|June 28, 2023
Summary
Concrete structures face rebar corrosion risks from chloride ingress and carbonation. Field specimens show lower material resistance than lab tests, especially with inadequate curing, impacting durability.
Area of Science:
- Civil Engineering
- Materials Science
- Corrosion Science
Background:
- Steel rebar corrosion in concrete is a major structural concern, driven by chloride ingress and carbonation.
- Existing models simulate corrosion initiation but often rely on lab-derived material properties.
- Discrepancies exist between laboratory material resistances and those from real structures, indicating performance gaps.
Purpose of the Study:
- To compare material resistance of concrete specimens under laboratory and field curing conditions.
- To evaluate the impact of different curing durations on concrete performance against corrosion factors.
- To investigate the influence of concrete composition and curing on resistance to chloride ingress and carbonation.
Main Methods:
- A comparative study involving laboratory specimens and on-site test walls/slabs from five construction sites.
- Standard European curing for lab specimens versus formwork curing (7 days) and limited surface curing (1 day) for field specimens.
- Testing of compressive strength, modulus of elasticity, chloride ingress resistance, and carbonation rate.
Main Results:
- Field specimens consistently exhibited lower material resistance (compressive strength, modulus of elasticity, chloride ingress, carbonation) than laboratory specimens.
- Shorter curing periods, particularly one day of surface curing, significantly degraded performance.
- Inadequate curing exacerbated the negative impact on chloride resistance and carbonation depth.
Conclusions:
- Laboratory-derived material properties may overestimate the real-world performance of concrete structures.
- Curing conditions significantly influence concrete durability and resistance to corrosion-inducing agents.
- Acceptance criteria should consider both delivered concrete quality and actual in-situ structural performance.
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