## 3 Results and Discussion
### Heat of Hydration  
To further demonstrate the impact of CSM doping on the hydration heat release of printing materials with varying w/c ratios, the hydration heat of the control sample without CSM was also measured. At the same time, in order to better present the test results and avoid too much data affecting the analysis, this study only compares and discusses the two groups of data with obvious differences in this section.  
In Figure 6a, there are three main exothermic peaks (A1, A2, A3). A1 peak refers to the release of heat of hydration water of C3S in cement; A2 peak refers to the hydrolysis of C3A, the formation of sulphoaluminate, and the hydration exotherm of GBPS; and A3 peak refers to the formation of AFM between residual C3A and ettringing [18]. It can be found from Figure 6a that the doping of CSM has no obvious effect on the A1 peak of the hydration heat curve but causes the A2 peak of the hydration curve to decrease and shift to the right.  
According to the XRD diagram, the main components in the CSM are Ca(OH)2 and CaO. When the CSM is added, the CaSO4 formed by Ca(OH)2 and Na2 SO4 in the CSM hinders the hydrolysis of anhydrous gypsum in cement, which inhibits the hydration hydrolysis of residual C3A in cement and makes the A2 peak shift to the right and decrease [18]. However, with an increase in the w/c ratio, the sample with CSM did not continue to move to the right and decreased as the blank sample.  
However, with an increase in the w/c ratio, the sample with CSM did not continue to move to the right and decreased as the blank sample. This may be because although  
Figure 6: Hydration heat analysis of different samples. (**a**) The incremental curves og heat flow vs. hydration (A1: heat of hydration water of C3S. A2: hydrolysis of C3A, the formation of sulphoaluminate, and the hydration exotherm of GBPS. A3: the formation of AFM between residual C3A and ettringite). (**b**) The cumulative exothermic curve.  
the increased water consumption will reduce the pH of the blank solution and hinder the hydration of the GBFS, for the samples with CSM, the increased water consumption will make more Ca(OH)\({}_{2}\) integrate into the pore solution, and the dissolved Ca(OH)\({}_{2}\) will participate in the synergistic strengthening of EVA rubber powder and dust ash, resulting in more NaOH and promoting the hydration of GBFS.  
This can also be proved by the right shift and upward trend of YN38 relative to YN37. In addition, it can be found from Figure 6a that the sample with CSM has a higher A3 peak than the blank sample, and this may be because the sample with CSM has more residual C\({}_{3}\)A; after the A2 peak, the SO\({}_{4}\)\({}^{2-}\) and Ca\({}^{2+}\) absorbed by the gel formed by the hydration of ore powder are released, and the residual C3A in the system continues to react to form Aft and Afm. As a result, the sample with CSM has higher heat release at the A3 peak.  
By comparing the cumulative heat release of different samples in Figure 6b, one can notice that, unlike the decrease in total heat release with an increase in w/c ratio for the blank sample, the sample with added slurry not only exhibits an increase in total heat release but also has the highest total heat release. This validates the conjecture of the aforementioned heat release curves, namely, that an increase in the w/c ratio leads to a decrease in the pH of the blank sample's pore solution, thereby delaying the hydration of GBFS. The increased water usage allows more Ca(OH)\({}_{2}\) to dissolve and participate in the synergistic effect with EVA powder and dust ash, thereby increasing the formation of NaOH and promoting the hydrolysis and hydration of GBFS. This also explains why calcining slurry can alleviate the adverse effects of increasing the water-to-cement ratio on the compressive strength of samples.