Christopher Alexander
University of South Florida, FL·Engineering·Early-career
Reinforced concrete holds up bridges, roads, buildings and seawalls, and the thing that most often ends its service life is rust. Chloride from seawater and de-icing salt reaches the steel bars inside the concrete and starts corrosion, which expands and cracks the surrounding material.
- Fields
Engineering
Materials Science
Earth & Environmental Science
- Topics
reinforced concrete
steel corrosion
chloride-induced corrosion
- Grants
- 1 known grant, through Jun 2029
What they work on
- Identify the steel-concrete interface conditions that cause chloride-induced corrosion pits to repassivate — reform a protective film and stop growing — rather than continue expanding into widespread damage.
- Quantify pit stability coefficients from single pit growth experiments while accounting for limits on the cathodic reaction set by moisture level and the porous, reactive nature of different cement binder formulations.
- Determine the kinetics and shape evolution of growing corrosion pits using split bipolar electrochemistry coupled to a multi-physics model, comparing different qualities of the steel-concrete interface.
- Calibrate a multi-scale damage forecasting model to exposure test results and use it to identify interface conditions that maximize corrosion durability in both traditional and carbon-sequestering concrete mixtures.
More about the research
This problem also blocks a promising route to lower-carbon construction: new cements that consume carbon dioxide are otherwise durable, but uncertainty about how steel corrodes inside them has kept them out of use. This project examines the thin zone where steel meets concrete and asks what conditions there can keep corrosion permanently in check.
Why it matters
Corrosion of reinforcing steel is a leading cause of deterioration in bridges, parking structures and marine infrastructure, driving enormous repair costs and premature replacement. Identifying steel-concrete interface conditions that keep pits from growing could support performance-based design specifications for longer-lasting structures, and could clear a barrier to adopting carbon-dioxide-consuming cements whose corrosion behavior is currently unproven.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Kimberly Kurtis
Georgia Institute of Technology, GA·Engineering
Determine how entrained air voids, tiny bubbles added to protect concrete, form and stay stable in low- and zero-clinker cement materials, using multiscale experiments and advanced characterization.
Carlos Moro
Texas State University, TX·Engineering
Determine how nanoscale additives change the crystal type, growth and distribution of calcium carbonate formed when cement-based materials are exposed to carbon dioxide, across different stages of carbonation.
Burkan Isgor
Oregon State University, OR·Materials Science
Develop laser-based additive manufacturing settings for functionally graded austenitic and duplex stainless steel claddings on curved carbon steel, using both wire and powder feedstocks.
The school
University of South Florida: 20 labs on PI Pages, $522M a year on research, 305 research doctorates a year.
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