## 2 Reverification of the Multicomponent Hydration Model
### Discussion on Spatial Condensed Water in Fine Micro-Pore Structures  
As pointed out above, excessive hydration was observed particularly in the analysis immediately after the exposure to 60 \({}^{\circ}\)C. To analyze the background of the modeling leading to such a critical concern, this section examines some numerical parameters simulated through the analysis. Figure 19 displays the numerical history of each porosity and its saturation degree, with the subscripts standing for capillary (cp), gel (gl) and interlayer pores (lr), in the case of Figure 16d. This Figure suggests that the saturation degree of capillary pores increases quickly due to the redistribution of water induced by the thermal loading from the age of 91 days, resulting in the disappearance of capillary pores with the precipitation of cement hydrates. After that, while gel pores begin to be filled gradually, their saturation degree increases up to 1.0 value. On the other hand, the numerical compressive strength in Figure 16d converges after the age of 120 days, where capillary pores completely disappear, due to the formulation of the compressive strength development model as described previously. Figure 18: Comparison of weight loss based on the modified model (W/C = 60%) [29]. In contrast to this analysis, the compressive strength in the experiment does not grow so quickly and greatly. Herein, focusing on each porosity at the age of 91 days which is the initial point of thermal loading in Figure 19a, it is found that the porosity of capillary, \(\varphi_{cp}\), is smaller than that of gel, \(\varphi_{gl}\). In the model, capillary pores are defined as the residual volume excluding the precipitated hydrates and unreacted particles in cement paste. Namely, the state of \(\varphi_{cp}<\varphi_{gl}\) is thought to be the state in which capillary pores left among hydration products become much less in volume, each being as fine as a gel pore, due to dense precipitation in open spaces. A schematic view is illustrated in Figure 20. In such fine micro-pore structures, it is possible that capillary and gel pores become almost closed or dead-end pores surrounded with a large amount of hydration products. Moreover, there is a concern that air voids stagnate in moisture transporting paths, preventing condensed water from moving around as pointed out in Reference [30]. In the original moisture equilibrium/transport model, if the seal-curing condition is changed from ordinary temperature to high temperature, the inner relative humidity increases due to redistribution of condensed water deriving from ink-bottle water trapped in capillary and gel pores apart from interlayer water. The modeling scheme on redistribution of condensed water is illustrated in Figure 21. However, this scheme is principally based on the hypothesis that capillary and gel pores are connected to one another, and moisture equilibrium/transport can occur easily and quickly. In short, wherever the redistributed water is condensed in capillary and gel pores, it can be available as free water for hydration in capillary pores in other spaces. Nevertheless, it is highly doubted whether the same hypothesis is applicable to such a case as fine micro-pore structures of a low W/C mixture after significant hydration. This is because it is supposed that most of the redistributed water is condensed in gel pores, occupying almost all the pores, and the water is difficult to be transported for hydration due to the quasi-closed structures as described above. Consequently, it was considered that the original model needs to be extended in consideration of spatial condensed water in fine micro-pore structures,  
Figure 19: Numerical history of each porosity and saturation degree of capillary, gel and interlayer pores in the case of Figure 16d. Figure 20: Schematic view of fine micro-pore structure resulting from dense precipitation of hydration products in open spaces. while being subjected to the basic scheme of Figure 21[24].