Content of research

The transport properties of porous materials such as concrete does not only depend on the porosity, but also on the spatial distribution of each phase. Therefore, the transport properties of HCP, which is a main component of concrete, was predicted. Figure 1 shows a cross section of HCP observed using a backscattered electron image, showing the distribution of each phase. We extracted each phase, calculated the autocorrelation function, and based on the results, distributed each phase in three-dimensional space to construct the three-dimensional spatial image model shown in Fig. 2. Figure 3 shows a comparison of the results of the diffusion coefficient calculated by the finite difference method and the measured values. The estimated and measured values agreed well with each other, even for different samples, indicating that the diffusion coefficients of hardened cement can be predicted using this model.

Potential for social implementation

• ・The diffusion coefficients of ions can be estimated accurately by applying a three-dimensional spatial image model constructed from the microscopic level as a method to evaluate the transport properties of cementitious materials.

Appealing points to industry and local governments

By constructing a three-dimensional spatial image model from the microstructure of cementitious materials, it is possible to predict the transport properties even when different materials are used. The model can also predict the change in performance, even when deterioration such as calcium leaching progresses, making it a useful tool for predicting the transport properties of concrete.