## 4 Conclusions  
This paper discusses the effects of adding QZ or FA on cement curing. The influence is primarily achieved through the physical effects of QZ (including the filling and nucleation effects) and the secondary hydration reaction of FA. 1. The compressive strength and UPV test results show that after replacing cement with FA, the early compressive strength and UPV value of the mortar specimen will decrease. However, after replacing cement with QZ, the mortar specimen's early compressive strength and UPV value will increase relatively. Compared with QZ, FA is more suitable for improving the compressive strength and UPV value of mortar specimens in the late stage, and the regression analysis model also arrives at a similar conclusion. This is mainly related to the early nucleation effect of QZ and FA's late secondary hydration effect;
2. The results from the hydration heat flow experiment show that after part of the cement is replaced by QZ, the time to reach the second hydration peak is shorter, and the peak value is higher. This is mainly because the nucleation effect of QZ accelerates the hydration rate of cement. The results from the cumulative hydration heat test show  
Figure 13: Strength-normalized CO\({}_{2}\) emissions versus the SCMs replacement rate. that the cumulative hydration heat of the samples decreases as more QZ and FA are added because of lesser cement content;
3. No new substances were produced in the sample during the XRD and FTIR experiments after FA and QZ partially replaced the cement. In addition, the XRD and FTIR experiments also show that calcium carbonate exists in the sample, and it reacts with aluminate to form monocarbonate aluminate;
4. The TG test results show that the chemically bound water content in the sample decreases after FA and QZ partially replace the cement. This is mainly because the cement content decreases when it is replaced by FA and QZ, resulting in a decrease in the number of hydration products in the sample;
5. SEM images show that after 28 days, as FA is added, additional hydration products are attached to the particle surface of the sample. These additional hydration products can improve the interface between FA and cement, which is attributed to the pozzolanic reaction of FA;
6. Carbon emission and energy consumption analysis showed that using both FA and QZ cementitious materials can significantly reduce CO\({}_{2}\) emissions and energy consumption. However, when the correlation between compressive strength and CO\({}_{2}\) emissions was considered comprehensively, the FA experimental group showed better results than the QZ group. This paper conducted a feasibility study for the large-scale and high-value utilization of FA and QZ, providing a promising solution for reducing the environmental impact of concrete without compromising its performance. However, there are also several areas for improvement in this study: 1. The regression model was developed based on a relatively small dataset. In future research, the volume of data should be increased, and the data should be divided into separate training and testing sets. 2. The environmental assessment method is relatively simple. Future research should consider more factors, such as workability and cost, to conduct a comprehensive evaluation. Validation, Y.M. and Y.L. ; formal analysis, Y.M. and Y.L. ; investigation, Y.M. ; resources, Y.M. ; data curation, Y.M. and Y.L. ; writing--original draft preparation, Y.M. ; writing--review and editing, Y.L., Y.Z., Z.W., Z.Z., X.W. and G.Z. ; supervision, G.Z. ; project administration, Z.W. ; funding acquisition, G.Z. All authors have read and agreed to the published version of the manuscript. This work was supported by the Senior Talent Foundation of Jiangsu University [grant no. JDKQ20240404] and the Natural Science Research of Jiangsu Higher Education Institutions of China [grant no. 24 KJB410002]. Not applicable. Data Availability Statement: Data will be made available upon request.