## 4 Conclusions  
In this study, the mechanical properties of HSCs containing pigments were determined, and the changes in the physical properties of ultra-high-strength cement composites due to the addition of actual pigments were demonstrated via thermal and XRD analyses. In addition, the hydrates generated in the test samples were analyzed using TGA. The differences in color expression of HSCs at different sample ages were identified via CIELAB analyses. R2 was evaluated from a correlation analysis, and the linear relationships between the obtained factors were determined. The following conclusions can be drawn from the results of this study:  
1. The initial strengths of the specimens mixed with pigments were lower than those of the specimens without a pigment in a steam-curing environment. However, the strength development accelerated with specimen age. The highest strength development was observed in the specimens mixed with 10% red pigment. Specimens containing the red pigment exhibited higher strengths than specimen P (without pigments) because of the presence of nano-Fe\({}_{2}\)O\({}_{3}\) particles in the former. This result shows the pore-filling effect of nano-Fe\({}_{2}\)O\({}_{3}\) particles. 2. Because of the high internal density of HSCs, the specimens mixed with pigments, except for R10, exhibited a lower shrinkage rate than specimen P. After the steam-curing process, the shrinkage of specimen R10 increased to 0.55% because of the accelerated internal hydration caused by the higher Fe\({}_{2}\)O\({}_{3}\) content in the red pigment compared to that of the R5 specimen. Figure 10: Specialized matrices showing the R2 distribution of each HSCC specimen at different ages: (a) 3 days, (b) 7 days, (c) 28 days, and (d) 3–28 days. The results of the differential thermal analysis using the stepwise method revealed that most of the hydration was completed during the initial steam-curing process. Specim G10 exhibited the highest combustion rate at approximately 300 \({}^{\circ}\)C because residual hydrates (Afm) were generated by the initial hydration delay. Furthermore, the hydration characteristics of the specimens that completed the steam-curing process were determined by calculating the residual mass (\(\Delta\)m) of calcium hydroxide. 4. In the analysis of the chromaticity and color difference of the specimens, the red-pigmented samples exhibited differences in chromaticity with increasing age, regardless of the pigment content, and the color difference exhibited a similar trend. For the green-pigmented specimens, the chromaticity remained constant with increasing pigment content, irrespective of the specimen age, but the color difference was considerable when the pigment content was approximately 5%. 5. The correlation of strength with the thermogravimetry, shrinkage, and color analysis results of C-UHSCC at different ages was analyzed, and R\({}^{2}\) tended to increase as the total TGA (\(\Delta\)m) decreased. This was because strength developed at the initial stages of aging. The correlation between the TGA intensity (\(\Delta\)m) and color components tended to increase with age. From the R\({}^{2}\) analysis at all ages, we observed the following. The lower the mixing rate, the higher the correlation between the intensity and L\({}^{*}\) in the R series. Furthermore, the higher the mixing rate, the higher the correlation between intensity and a\({}^{*}\). The G series exhibited a high correlation with a\({}^{*}\) regardless of the incorporation rate. This study analyzed the correlations of specific factors influencing the strength of colored cement composites. However, further research is required to determine whether these correlations are valid for UHPC mixing. The results of this study could serve as a guideline for future studies investigating the effect of pigment addition on the performance of cementitious composites. Conceptualization, S.P., G.K., D.J. and J.N. ; Methodology, S.P., B.C. and M.K. ; Supervision, S.P. and J.N. ; Writing--original draft, S.P., G.K., G.C., N.P., D.J., B.C., M.K.