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At Durability Engineers, our experts have a deep seated understanding of the mechanisms and potential for Delayed-Ettringite Formation (DEF), and justly the importance of proper mass concrete design. We use this knowledge to provide our clients with consulting solutions during project planning and design, as well as in evaluation of existing structures.



Delayed-Ettringite Formation (DEF) is a latent expansive reaction stemming from the formation of ettringite particles within the cement paste. At ambient temperature curing, ettringite forms as a part of the “normal” hydration process of portland cement.  However, when concrete is exposed to excessive temperatures during curing, ettringite formation is hampered and forced to form at later ages. This delayed formation of ettringite can lead to internal expansion, uncontrollable cracking, leading to corrosion of reinforcing steel, loss of structural integrity and ultimately reduction in service-life.

What is DEF


For new structures, Durability Engineers performs peer review of concrete proportioning, drawings and specifications to evaluate the potential and/or susceptibility of DEF. In new construction, our team assists with materials selection, mixture design optimization and thermal control plans to prevent DEF from occurring. We develop an engineering strategy that provides mitigation approaches for each structure.  Our services include:

  • Specification Development

  • Materials Selection

  • Mixture Proportioning

  • Standard and Specialty Testing

DEF Prevention and Mitigation
Concrete Residual Expansion Measurements Field Evaluation


In existing concrete structures, we employ state of the art techniques to evaluate existing conditions, identify the cause of deterioration and determine the potential for continued deterioration.   We extract samples of the concrete and examine them in our laboratories for more in-depth characterization and testing. We augment and validate results from field investigations with petrographic and laboratory assessments. Our team provides:

  • On-site Evaluations,

  • Assessment of Existing Conditions,

  • Non-Destructive and Destructive Testing,

  • Oversight of Sample Removal,

  • Specialty DEF Testing to Determine Diagnosis and Prognosis

  • Instrumentation and Monitoring of the Structure In-situ

  • Standard and Specialty Testing

DEF Evaluation


Principal Engineer, Dr. Anthony Bentivegna recently co-authored a report on novel test methods for determination of delayed ettringite formation (DEF) in mass concrete. The published paper discusses the use of mortar bar testing in the laboratory as a means of representing concretes that experience high early-age temperature profiles and potential risk for DEF. 

Concerned about your Structure's Susceptibility to DEF, Durability Engineers Can Help...

Our team assists our clients through the development of standardized and specialty testing programs to determine the potential for DEF in new and existing structures. 

DEF Map 2.bmp

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