Dr. Kalliontzis is an active member in the following Committees and Organizations:
Associate Member in American Concrete Institute (ACI) Committee 239: Ultra-High-Performance Concrete
Voting Member in ACI Subcommittee 239-C: Structural Design on UHPC
Associate Member in ACI Committee 357: Offshore and Marine Concrete Structures
Associate Member in ACI Committee 550: Precast Structures—Joint ACI-ASCE
Voting Member in The Masonry Society (TMS) Research Committee and Corresponding Member in the Reinforcement & Connectors (RC) Subcommittee
Member in the University Marine Energy Research Community (UMERC)
Member in the Texas Masonry Council (TMC) Industry Development and Education Alliance (IDEA) Committee
Member of the StEER Network
Dr. Kalliontzis has served in the Scientific Committee for the 3rd International Interactive Symposium on Ultra-High Performance Concrete (UHPC). He has also organized the first and second UH Masonry Days for 2022 and 2023.
He has also participated in several reconnaissance (PVRR and EARR) reports of StEER for historic tropical storms and hurricanes.