Hokkaido University Research Profiles

Manufacturing Technology

Development of a Non-destructive CT-XRD Coupling Method and Its Application

Visualization of the microstructure of hardened cement

To develop innovative cement-hardening materials, we are devising a non-destructive integrated CT-XRD method, a novel measurement method combining the CT method to obtain geometric and spatial information on microstructures inside concrete with an accuracy of several microns, and a diffraction method to investigate hydrates and alterations in the region of interest.

Content of research

Concrete is structurally hardened by binding rock (aggregate) through a hydration reaction between cement and water. As a structural material, concrete is intended to withstand loading and certain weather/environmental conditions, but these may cause cracking of the concrete, which may progressively deteriorate due to strong acids and other chemical reactions caused by erosion and materials from the atmosphere, seawater and groundwater that come in contact with it. To stably use the social infrastructure for a long period of time, it is important to be able to see inside the internal structure of concrete with “bug eyes” and find any abnormalities that have occurred.
With the pioneering “non-destructive integrated CT-XRD method,” the sample is irradiated with high-intensity X-rays from synchrotron radiation to selectively visualize 3D structures from transmitted monochromatic X-rays at 25 keV. Energy-dispersive X-ray diffraction is also performed in specific regions of interest through multiple slit operations to identify hydrates (portlandite, calcite, etc.), their alteration and aggregate minerals.

  • Conceptual diagram of the non-destructive integrated CT-XRD method

  • CT images of cracks (left) and comparison of diffraction maps before and after degradation at the observed coordinates (right)

Potential for social implementation

  • ・A new method of evaluating microstructure based on fluoroscopy technology for instrument development
  • ・Clarifying degradation and damage phenomena of hardened cement, and developing innovative cementitious materials that can self-restore without cracking or deteriorating

Appealing points to industry and local governments

Concrete is extensively used in deep underground, submarine and marine environments, as well as in highly acidic, hot, and cold environments, and must be durable for hundreds to tens of thousands of years. Since the concrete material includes industrial by-products such as fly ash and blast furnace slag, it has greater flexibility for material design. To develop highly-efficient and highly functional concrete, we are conducting research and development on material design methods that will enable us to use the right materials in the right places.