Date: 

27th September, 2026 

Venue:

HASEKO-KUMA Hall, the University of Tokyo, Hongo Campus, 7-3-1,
Hongo, Bunkyo-ku, Tokyo, Japan (info Map)

Prof. Ippei Maruyama

Conference Chair, the University of Tokyo

Lecture:
Basics of carbonation of concrete
Mineralization and carbonation hardening are fundamentally governed by the same underlying mechanisms as the carbonation of concrete, a phenomenon that has long been studied in the context of concrete durability. This lecture aims to revisit the historical development of research on concrete carbonation and neutralization, provide an overview of recent advances in the field, and present a comprehensive perspective on the fundamental mechanisms that underpin a wide range of emerging technologies.

Particular emphasis will be placed on the coupled transport of moisture and CO₂ within porous cementitious materials and the resulting carbonation processes. Through selected examples from both fundamental and applied research, the lecture will introduce recent findings that have advanced our understanding of these coupled physicochemical phenomena and discuss how this knowledge serves as the scientific foundation for the development of mineralization technologies and carbonation hardening.

Prof. Thomas Matschei

Dr. Zajac MACIEJ

Team Leader Scientific Coordination, Global Research & Development and Innovation, Heidelberg Materials AG

Dr. Maciej Zajac is Team Leader Scientific Coordination at Heidelberg Materials Global R&D in Leimen. His research focuses on the new technologies for cement and concrete, including hydration mechanisms, supplementary cementitious materials, carbonation, concrete recycling and alternative methods of cement production. He combines fundamental materials science with industrial implementation and standardization.

Lecture:
Carbonation Hardening of Cementitious Materials: Mechanisms, Performance and Industrial Boundaries

Carbonation hardening is a CO₂-curing technology in which clinker phases and early hydrates react with dissolved CO₂ to form calcium carbonate, silica-rich gels and, depending on curing history, secondary hydrate phases. This lecture introduces the mechanism from Portland cement to Portland-limestone and belitic systems. The dominant process is not ordinary hydration acceleration, but a coupled dissolution, carbonation and rehydration sequence controlled by CO₂ access, water availability, carbonate precipitation and remaining clinker reactivity. In Portland cements, alite and belite carbonation, partial C-S-H decalcification and subsequent hydrate formation refine the microstructure and improve early strength. Limestone mainly modifies carbonate availability and dilution, while belitic binders require carbonation to overcome intrinsically slow hydration. The talk will separate thermodynamic driving forces from kinetic limitations, discuss pore blocking and scale-up constraints, and evaluate where carbonation hardening is scientifically robust, industrially useful, or still unresolved for precast and low-CO₂ cement production.

Dr. Takahiro Okubo

Chiba University, Faculty of Engineering, Department of Applied Chemistry and Biotechnology

Dr. Takahiro Ohkubo is an Associate Professor at Chiba University. His expertise includes NMR spectroscopy, DFT calculations, and MD simulations. His research focuses on disordered and poorly crystalline materials, such as glasses and clay minerals. In recent years, He has been applying atomistic simulations to carbonation-related processes in cementitious materials.

Lecture:
Atomistic Modeling of Cementitious Materials: From Classical to Machine-Learning Interatomic Potentials
Molecular dynamics (MD) simulations originated in the late 1950s and have since been applied to a wide range of materials, including cementitious materials. They are now widely used to understand structures and the dynamic behavior of atoms and molecules that are difficult to observe directly by experimental methods. In this lecture, I will outline the fundamental theory of MD simulations and discuss key concepts for applying them to cementitious materials, including modeling strategies and interatomic potentials. I will also introduce machine-learning interatomic potentials, a rapidly developing field in recent years, with a focus on their basic principles and current applications.

Dr. Ryo Kurihara

Department of Architecture, Graduate School of Engineering, The University of Tokyo

Dr. Ryo Kurihara is an Assistant Professor at the University of Tokyo. His research expertise lies in the microstructural characterization of cementitious materials, focusing on their structural evolution in response to hydration, drying/wetting and carbonation processes. Since his PhD studies, he has applied 1H NMR relaxometry techniques to investigate the pore structures and moisture dynamics of cement-based materials.

Lecture:
Application of 1H NMR relaxometry on cement-based materials: From Basic to Current Perspectives

1H NMR relaxometry has been widely applied to evaluate the pore structure of cementitious materials. As this technique does not require sample pre-treatment, it offers significant advantages for investigating C-S-H gel structures compared to other experimental methods. In this lecture, I will outline the fundamental principles of 1H NMR relaxometry, including common pulse sequences and key assumptions for interpreting pore structures. Furthermore, I will introduce landmark studies and recent applications in the field of cement chemistry, followed by a discussion on current challenges.