Surface layer measurements of early age mortar investigated by ultrasonic guided waves and finite element analysis

Jacob L. Borgerson, Henrique Reis

Research output: Contribution to journalConference articlepeer-review


A pulse-echo ultrasonic guided wave approach that monitors the development of early age mortar during the initial stages of setting and hardening is presented. The method transmits the fundamental torsional wave mode on one end of a cylindrical steel rod partially embedded in mortar and then monitors the reflected signals. Both the reflection from the end of the rod and the reflection from the point where the waveguide enters the material are monitored. The development of the material's mechanical properties is related to the change in signal strength of the reflections. The reflection at the location where the waveguide pierces the material is essentially a surface measurement. It is known that the material properties of concrete vary with depth; specifically, the material in the surface layer possess different material properties than the core material of the specimen. Finite element analysis was used to analyze these differences and to provide a clearer understanding of the entry-reflection. The analysis shows that at early stages, it takes more time for the surface layer to achieve the same properties as that of the core of the specimen. However, after the mortar has achieved measurable strength (e.g. 12-14 hours), the material properties of the surface layer can reasonably approximate those of the core of the specimen.

Original languageEnglish (US)
Article number69321E
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jun 2 2008
EventSensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2008 - San Diego, CA, United States
Duration: Mar 10 2008Mar 13 2008


  • Concrete
  • Early age mortar
  • Finite element analysis
  • Guided waves
  • Pulse-echo
  • Ultrasonics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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