## 5 Results and Discussion
### Mineralogy Analysis and Validation  
Figure 5 summarizes the XRD patterns of the specimens that were involved in the thermodynamic model and the two additional JA4 and PNS6 specimens. The XRD patterns of the specimens from the JA series and PNS series are presented in Figure 5a,b, respectively, and a detailed diagram of the 2\(\theta\) range 27.8\({}^{\circ}\)-30.0\({}^{\circ}\) is shown in Figure 5a. The curing period was fixed to 168 h due to the thermodynamic analysis revealing that the investigated reaction products tended to precipitate in most of the specimens prior to this time. The XRD patterns revealed that the reactants and products of the modified specimens were basically the same as the CS specimen, but the reflection intensity was altered by the admixture type and dose. The reactants that were detected by the X-ray diffractometer were the soil minerals within the raw materials, with the clinkers being undetectable due to the relatively high hydration rate. The common products that were detected in all patterns included CSH, AFt, gismondine and Na zeolite. Meanwhile, the reaction products CSH and Na zeolite also produced humps within the approximate 2\(\theta\) range of 30-34\({}^{\circ}\)[44; 45] in every pattern, which were the major diffraction characteristics of those minerals. Notably, the Na zeolite in this study was composed of nat  
Figure 4: The correlation analysis of the _SI_ values of Ca(OH)\({}_{2}\) and those of CSH, AFt and natrolite. The modification effects of the admixtures on the cement hydrates that were revealed by the XRD technique coincided with those that were revealed by the _SI_ analyses. In terms of CSH, limited information was provided by the intensity change of the humps due to its highly amorphous nature. Nevertheless, except for the JA dose of 1.2%, the addition of the admixtures improved the reflection intensity of CSH at around 28.3\({}^{\circ}\) and 29.4\({}^{\circ}\) compared to the CS specimen (to different magnitudes), with the improvements from the PNS doses of 1.2% and 1.8% exceeding those from the JA doses of 0.4% and 0.8%. The refection intensity of gismondine at 27.9\({}^{\circ}\) gave rise to a similar change pattern as that for CSH, implying that gismondine shared some reactants with CSH. Notably, a detailed diagram for the JA12 specimen showed that the reflection intensities of CSH and gismondine were substantially reduced by an excessive dose of JA and that a CO\({}_{2}\)-containing silicate of tilelyite (Ca5 Si2O7(CO3)2) was formed. [PERSON] et al. [46] addressed the fact that CO\({}_{2}\)-containing silicates (such as tilleyite), of which the cementing strength is relatively low, are the preferentially stable phase of calcium silicates under the coupled conditions of CO\({}_{2}\) presence and insufficient Ca(OH)\({}_{2}\). With this finding, our detailed diagram suggested that  
Figure 5: The XRD patterns of the specimens after 168 h: CS and the JA series (**a**) and CS and the PNS series (**b**). Mt, montmorillonite; Mus, muscovite; Q, quartz; A, albite; AFt, ettrine; Z, Na zeolite; G, gismondine; CSH, calcium silicate hydrate; T, tilelyite. the excessively high alkalinity of the pore solution led to the carbonation of the clinkers, thereby decreasing the compressive strength of the specimen [47,48]. Compared to CSH, the admixture addition produced a more prominent intensity change in the reflection of AFt. The intensity of the AFt reflection was 1066 in the CS specimen and a JA dose of 0.4% produced the highest intensity of the AFt reflection (1533), while the optimum JA dose (0.8%) produced a reflection intensity of 1300 and the excessive dose (1.2%) reduced the intensity to 802, which was lower than that of the CS specimen. The PNS doses of 0.6%, 1.2% and 1.8% produced reflection intensities of 1258, 1223 and 1153, respectively. The dose effects of PNS were similar to those of JA, but the inhibition of AFt formation did not occur. The peak intensity of AFt occurred at low doses in both the JA and PNS series.