## 4 Conclusions  
The findings of this study have high potential for practical application. The use of new pozzolanic materials is crucial for the quality of engineering projects. FA is already an accepted pozzolanic material in ready-mix concrete, and market acceptance is likely to be even higher for FGCBA, which has a similar chemical composition. More importantly, there are limited storage tanks in ready-mix concrete plants, and it was demonstrated in this study that FGCBA can be used in ready-mix concrete by simply adding a water-reducing agent. This enables FA and FGCBA to be co-utilized in the same storage tank without needing to control their proportions before storage. 1. The study reveals that FGCBA has notable pozzolanic potential, particularly in its ability to surpass ASTM C618 requirements at 28 days and exhibit superior long-term strength compared to Type I cement. 2. FA enhances workability, evidenced by increased slumps at all tested water-binder ratios. Conversely, the amount of FGCBA used as replacement requires careful consideration in terms of the mix design as it improves workability only up to a 20% replacement level before the slump values decrease. Figure 16: Voids in concrete at different W/B ratios and cement replacement levels for (**a**) FA; (**b**) FGCBA. Figure 15: Density variation in concrete using FGCBA as a cement substitute at various W/B ratios of (**a**) 0.4; (**b**) 0.45; (**c**) 0.5. 3. In terms of air content and unit weight, both FA and coal bottom ash reduce the density of concrete, with FA creating a lighter mix. The impact on air content becomes more pronounced with higher percentages and water-binder ratios. 4. The setting time is extended through the addition of both materials, which is beneficial for prolonged workability but may necessitate schedule adjustments or the use of admixtures in construction. 5. FA is particularly effective at enhancing long-term compressive strength, making it suitable for durability and performance needs. FGCBA contributes to gradual strength gains, indicating its appropriateness in applications in which moderate strength development is adequate. 6. Drying shrinkage is influenced by both materials and varies with water-binder ratios and replacement percentages. FA consistently increases shrinkage over replacement percentages, while the effect of FGCBA is more variable, necessitating careful consideration in the mix design for structural stability. 7. Chloride permeability tests show that 20% FA replacement optimizes durability by reducing permeability. At higher replacement levels, the effectiveness diminishes. FGCBA significantly improves impermeability, especially at increased replacement percentages, enhancing the material's potential in durable concrete formulations. 8. The use of FGCBA as a cement replacement in concrete notably influences its absorption, density, and voids. Higher FGCBA replacement levels lead to increased absorption and void content, suggesting a more porous structure. While enhancing certain durability aspects, these changes highlight the need for careful consideration in mix design, especially at elevated replacement rates, to maintain concrete's structural integrity and durability. Conceptualization, T.-A.C.; methodology, T.-A.C.; validation, T.-A.C.; investigation, C.-W.C.; resources, T.-A.C.; data curation, T.-A.C.; writing--original draft preparation, C.-W.C.; writing--review and editing, T.-A.C. and R.H.; visualization, T.-A.C.; supervision, T.-A.C.; project administration, T.-A.C.; funding acquisition, T.-A.C. All authors have read and agreed to the published version of the manuscript. This research was funded by the Ministry of Science and Technology, Taiwan, ROC, under grant MOST 109-2622-E-019-008. Not applicable. The data presented in this study are available on request from the corresponding author. The data are not publicly available due to [PERSON] has not graduated yet. Author [PERSON] was the founder of the Astray Limited Company.