Dr. Kalliontzis is an active member of the following Committees and Organizations:
2026 Board of Directors Member in the University Marine Energy Research Community (UMERC) - Sponsored Program by the U.S. Department of Energy Water Power Technologies Office (DOE - WPTO)
Associate Member of American Concrete Institute (ACI) Committee 239: Ultra-High-Performance Concrete
Voting Member of ACI Subcommittee 239-C: Structural Design on UHPC
Associate Member of ACI Committee 357: Offshore and Marine Concrete Structures
Voting Member of ACI Committee 550: Precast Structures—Joint ACI-ASCE
Chair of ACI Subcommittee 550: PRESS FRAME
Voting Member of The Masonry Society (TMS) Research Committee
Voting Member of The Masonry Society (TMS) Reinforcement & Connectors (RC) Subcommittee
Chair of High-Strength Reinforcing Bar (HSRB) Task Group for The Masonry Society (TMS)
Member of the Texas Masonry Council (TMC) Industry Development and Education Alliance (IDEA) Committee
Member Level 2 of the National Science Foundation’s StEER Network
Other Professional Service and Outreach Activities:
Chair of the Student Competition for the 2026 4th International Interactive Symposium on Ultra-High Performance Concrete (4IISUHPC).
Member of the Scientific Committee for the 2026 International Masonry Conference.
Gave several expert-opinion media interviews for the 2024 Houston Derecho event.
Member of the Scientific Committee for the 2023 3rd International Interactive Symposium on Ultra-High Performance Concrete (3IISUHPC).
Invited External Examiner for the Final Thesis Defense of a PhD Candidate in the University of Alberta, Canada (2025).
Participated in the NICHE Workshop “Designing the World’s Largest Wind-Wave Research Facility” DesignSafe-CI (2024).
Organized UH Educational Masonry Days (2022-2023).
Participated in several reconnaissance (PVRR and EARR) reports of StEER for historic tropical storms and hurricanes (2022-2024).