Terry Willems

Terry Willems

Senior Principal Materials Scientist

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At CTLGroup, Mr. Willems’ responsibilities include consulting and testing associated with construction materials evaluation, troubleshooting material performance problems, durability evaluations, and forensic investigations and litigation support. He has experience in the evaluation of concrete, mortar, grout, resilient floor covering materials, ceramic tile, epoxy terrazzo, and floor underlayments, among other materials. Mr. Willems has also evaluated over a million square feet of tile systems and their failures, including on-grade, above-grade, swimming pools, showers, and exterior tile systems such as plazas and balconies.

Mr. Willems capabilities also includes petrographic examination of concrete and other construction materials to ascertain causes of deterioration, identify materials, and assess quality for repair and rehabilitation projects. He has supervised and performed numerous field and laboratory forensic investigations of materials performance issues, and his contract reports include definitive findings regarding causes of damage and deterioration, materials testing, analysis and development of repair procedures, specifications and drawings. As an experience expert witness, Mr. Willems has testified in over 40 cases. His career was inspired by his passion for solving problems, and working at CTLGroup has offered a wide variety of challenges from working on new construction, to facilities involved with the space shuttle program, to historic structures built in the 1800s.


B.S. in Water Resource Management and Soils

University of Wisconsin – Stevens Point, 1977


Willems, T., Jennings, V. 2014. “Thaumasite Sulfate Attack of Precast Concrete Retaining Wall Units.” Presented at Spring 2014 Session on Thaumasite Sulfate Attack: Sponsoring Committee ACI 201 Durability of Concrete.

Lee, S.Y., Daugherty, A., Willems, T. 2013. “Application of Petrographic Analysis for Corrosion Assessment.” Presented at 2013 Fall ACI Convention: Sponsoring Committee 222 – Corrosion of Metals in Concrete-Laboratory Test Methods for Corrosion Assessment: Technical Review and Practical Implications, Part 1.

Lee, S.Y., Willems, T. 2013. “Case Study on Concrete Pavers Exhibiting Physical Salt Attack.” Presented at 2013 Fall ACI Convention: Sponsoring Committee 123 – Research and Current Developments. Open Paper Session, Part 1 of 2.

Bebler, S., Powers, L., Willems, T., and Detwiler, R. 2002. “Petrographic Examination Used to Analyze a Distressed Sewer Line Coating.” Journal of Protective Coatings and Linings, Vol. 19, No. 5: 49-52. May.

Farahmandpour, K., Jennings, V., Willems, T., and Davis, A. 2002. “Evaluation Techniques for Concrete Building Envelope Components.” Interface, Vol. XX, No. 3: 3-15. March.

Farahmandpour, K., T. J. Willems, A. G. Davis. 2001. “Evaluation of Liquid-Applied Waterproofing Systems: Case Histories.” Interface. 21-31. October.

Willems, T., and Kanare, H. 2000. Investigating Floor Moisture Problems Using Automated Long-Term Monitoring of Relative Humidity.” Vaisala News.

Burg, R., M. Caldarone, M., Detwiler, G. Jansen, C., and Willems, T. 1999. “Compressive Testing of HSC: Latest Technology.” Concrete International. Vol. 21, No. 8: 67-76. August.

Pistilli, M. and Willems, T. 1993. “Evaluation of Cylinder Size and Capping Method in Compression Strength Testing of Concrete.” Cement, Concrete, and Aggregates, CCAGDP, Vol. 15, No. 1: 59-69.

  • American Concrete Institute
  • Cast Stone Institute
  • National Tile Contractors Association
  • The Society for Protective Coatings
  • ACI Wason Medal for Materials Research, 2001

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