Associate Research Scientist (PREP0005163)

work that underpins the scientific research of the collaboration.

Research Title: Accelerated Corrosion Studies of Reinforced Concrete

The Infrastructure Materials Group (IMG) is seeking a highly motivated Research Associate to be a part of the Next-Generation Building Standards initiative within NIST.

Degradation of reinforced concrete due to embedded steel corrosion remains a monumental challenge, with direct and indirect costs accounting for approximately 6% of the U.S. Gross Domestic Product. Current building codes, testing standards, and common-practice heuristics, such as diffusion coefficient, depth of cover, and chloride per unit mass of cement, are inadequate for assessing the complex environmental factors and novel binder chemistries that most strongly affect structural service life. To address this, the IMG "Assessing Steel Corrosion Risk in Innovative Cement Concretes" project aims to integrate advanced electrochemical characterization with species-transport modeling. We are seeking a highly motivated Postdoctoral Researcher with academic training and experience in corrosion science to develop new metrology standards specific to reinforced concrete structures, which are often in unsaturated conditions. The selected candidate will focus on measuring the precise rates of corrosion initiation and progression, ultimately providing the foundational data needed to build high-fidelity service-life and fragility models for reinforced concrete structures.

The National Institute of Standards and Technology (NIST) promotes U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology to enhance economic security and improve our quality of life. Located in Gaithersburg, Maryland, NIST offers a collaborative, interdisciplinary culture where you will work alongside some of the world's leading scientists and engineers to solve critical national challenges.

IMG at NIST serves as an important resource for developing science-based tools and measurement standards to enhance the resilience and sustainability of the nation's physical infrastructure. As part of the Engineering Laboratory, the IMG focuses on predicting the service life of infrastructure components under real-world and accelerated weathering conditions.

We are specifically targeting a researcher with a rigorous background in developing accelerated corrosion studies to inform long-term modeling and prediction of degradation. The ideal candidate does not just run standard tests; they understand the thermodynamic mechanisms that drive durability and those that drive corrosion initiation and propagation. You should be comfortable moving between the wet lab (extracting and analyzing pore solutions) and the computer (modeling phase assemblages and quantifying uncertainty).

Experience with cement pore solution chemistry and concrete transport properties, such as determining the Formation Factor using XRF for pore solution analysis or modeling hydration kinetics using GEMS/PHREEQC, is a critical skill needed for this position. Experience designing and conducting advanced electrochemical assessments of reinforcement steel to measure corrosion initiation and progression rates under varied solution properties and environmental conditions are required.

Key responsibilities will include but are not limited to:

The Research Associate will conduct advanced accelerated corrosion studies of steel embedded in concrete made with innovative cement binders to develop new metrology for assessing corrosion degradation in new and existing reinforced concrete structures.

Cement and Concrete Material Science

• Advance Measurement Science: Develop and validate novel test methods for characterizing alternative cementitious materials, with a specific focus on linking microstructural development to macro-scale transport properties.
• Pore Solution Characterization: Lead efforts to standardize X-ray Fluorescence (XRF) techniques for the elemental analysis of concrete pore solutions, establishing protocols for characterizing accuracy and repeatability.
• Durability Modeling: Apply thermodynamic modeling to predict phase changes (e.g., carbonation, chloride binding) in Type IL and CSA cements under varying climate scenarios.

Corrosion Science

• Advanced Data Collection: Utilize Electrochemical Impedance Spectroscopy (EIS), potentiodynamic polarization, open-circuit potential (OCP), and linear polarization resistance (LPR) to accurately quantify corrosion current density, corrosion potential, and charge transfer resistance. Also, develop measurement plans to obtain Point Defect Model (PDM) parameters for modeling rebar passivation and passive film breakdown.
• Microstructural Characterization: Perform high-resolution materials characterization utilizing Scanning Electron Microscopy- Energy Dispersive X-Ray Spectroscopy (SEM-EDS) to study the steel-concrete interface and understand the morphology of localized degradation.
• Model Integration: Translate fundamental bench-top corrosion data and transport property measurements into accurate inputs for numerical and structural models, connecting atomic-level physicochemical mechanisms to building-scale performance.

Technology Transfer

• Uncertainty Quantification: Use advanced statistical frameworks (Bayesian inference, Monte Carlo simulations) to analyze experimental data, and to quantify the uncertainty in service-life predictions for code development.
• Code & Standard Development: Translate research findings into actionable proposals for ASTM and ACI committees, directly influencing the next generation of building codes.

Qualifications

Required

• Education: Successful candidates should have completed a Ph.D. in any one of Chemistry, Physics, Mechanical Engineering, Chemical Engineering, Civil Engineering, or Materials Science at the time of the position start date, with a focus on chemistry and material science of cementitious materials or corrosion.
• Cementitious Materials Science Background: Demonstrated experience conducting quantitative laboratory measurements on cementitious materials: X-ray diffraction (XRD), thermogravimetric analysis (TGA), isothermal calorimetry, scanning electron microscopy (SEM).
  • Transport & Durability: Demonstrated understanding of the Nernst-Einstein relationship, electrical resistivity measurements, and the determination of the Formation Factor in cementitious systems.
  • Thermodynamic Modeling: Proficiency with geochemical modeling software (e.g., GEMS, PHREEQC, or Oli) to simulate cement hydration and phase stability in low-carbon binders.
  • Alternative Binder Expertise: Demonstrated research experience with Calcium Sulfoaluminate (CSA) cements, Type IL cements, or alkali-activated materials.
• Corrosion Science Background: Demonstrated expertise in investigating corrosion mechanisms of metallic systems under a range of environmental and solution conditions.
  • Strong experience designing and executing laboratory experiments to study corrosion processes, including controlled electrochemical testing and environmental exposure studies.
  • Hands-on laboratory experience with Electrochemical Impedance Spectroscopy (EIS) and Mott-Schottky Analysis
  • Experience with atmospheric corrosion and field exposure studies in marine environments, including sample design, deployment, and post-exposure analysis.
  • Familiarity with accelerated corrosion testing methodologies and relevant ASTM and AMPP standards, particularly those related to corrosion rate measurements and chloride-induced corrosion in reinforced concrete systems.
• A strong record of scientific productivity, evidenced by publications in peer-reviewed journals.

Preferred

• Quantitative Phase Analysis (QPA) using X-ray Diffraction, including the use of the Internal Standard Method to quantify amorphous contents in hydrated cementitious systems.
• Composition Analysis using X-ray fluorescence to quantify the elemental composition of solutions.
• Proficiency in surface/sample preparation of metals for metallographic analysis and advanced microstructural characterization techniques, specifically Scanning Electron Microscopy- Energy Dispersive X-Ray Spectroscopy (SEM/EDS), Raman spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), optical profilometry, optical microscopy, and ion chromatography.

U.S. Citizen is Preferred

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Salary Range

The referenced salary range represents the minimum and maximum salaries for this position and is based on Johns Hopkins University's good faith belief at the time of posting. Not all candidates will be eligible for the upper end of the salary range. The actual compensation offered to the selected candidate may vary and will ultimately depend on multiple factors, which may include the successful candidate's geographic location, skills, work experience, internal equity, market conditions, education/training and other factors, as reasonably determined by the University.

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