## 3 Experimental Test Results
### Engineering Properties  
Figure 5 shows the measured values of slump and air content of OPC and FA compared with GGBFS by [PERSON] [26] for fresh concrete by the admixture mixing rate. The slumps of GGBFS and FA were 165-205 mm and 195-205 mm, whereas the air contents were 4.1%-5.3% and 4.6%-5.7%, respectively. Therefore, the slump was suitable for the target value of 180 \(\pm\) 25 mm, and the air content also was within the standards of 4.5% \(\pm\) 1.5% for all mixing proportions. Under the same mixing conditions, both the slump and air content of FA were found to have lower properties than those of GGBFS. In this study, to examine the influences of the admixture type and mixing rate on workability, the water content required to guarantee the target slump range of 180 \(\pm\) 25 mm was measured after fixing the unit binder content and chemical admixture content at 330 and 2.31 kg/m\({}^{3}\), respectively. As shown in Figure 6, it was found that the unit water content decreased by approximately 2.75 kg/m\({}^{3}\) for GGBFS and 3.00 kg/m\({}^{3}\) for FA as the admixture mixing rate increased by 10%. This indicates that workability can be improved through the substitution of the admixtures under the same unit binder content  
Figure 4: X-ray diffraction patterns of OPC and FA compared with GGBFS as measured by [PERSON], adapted from [26].  
Figure 3: Gradation sieve analysis curves of the aggregates: (**a**) mixed fine aggregates; (**b**) coarse aggregates.  
conditions, and that FA demonstrates a higher workability improvement effect than GGBFS at the same mixing rate.  
Figure 7 shows the compressive strength of OPC and FA compared with GGBFS by [PERSON] (2018) at different ages for each admixture mixing rate. Overall, FA exhibited less compressive strength development with aging than GGBFS. At 3 and 7 days of aging, the GGBFS and FA specimens began to show a difference in compressive strengths when the admixture mixing rate was 40%. At 28 and 56 days of age, conversely, a difference in these compressive strengths occurred when the admixture mixing rates were 10% and 30%, respectively. To examine the compressive strength development rate with aging, the compressive strength rate--compressive strength of FA/compressive strength of GGBFS--was calculated according to the admixture mixing rate, as shown in Figure 8. The result showed a tendency to decrease along the curve of a quadratic equation as the admixture mixing rate increased, even though the error range increased.  
Figure 9 shows that the compressive strength tended to slightly decrease, except at 28 days of aging, as the GGBFS mixing rate increased. FA exhibited larger decrements in compressive strength than GGBFS at all ages. To examine the long-term strength development rate of each admixture after 28 days of aging, an analysis was conducted, as shown in Figure 10. Both GGBFS and FA exhibited high long-term strength development rates as the mixing rate exceeded 15%. In particular, the development  
Figure 5: Results of the air content and slump values of OPC and FA compared with GGBFS as measured by [PERSON] (adapted from [PERSON] (2018)) in terms of the mixing rate.  
Figure 6: Results of the unit water content of OPC and FA compared with GGBFS as measured by [PERSON] (adapted from [PERSON] (2018)) in terms of the mixing rate.  
rate of GGBFS was higher than that of FA, indicating that GGBFS has a higher strength improvement effect after 28 days than FA at the same mixing rate.  
Figure 8: Result of compressive strength (FA)/compressive strength (GGBFS) as measured by [PERSON] (adapted from [26]) in terms of the mixing rate.  
Figure 7: Results of the compressive strength of OPC and FA compared with GGBFS as measured by [PERSON] (adapted from [26]) by age.  
Figure 9: Results of the compressive strength of OPC and FA compared with GGBFS as measured by [PERSON] (adapted from [26]) in terms of the mixing rate.