## 5 Results and Discussion
### Modeling Results and Analysis  
#### 5.3.1 Influences of the Admixtures on the Chemical States of the Compositional Minerals  
With the pore solution data, the modeling results were calculated. The compositional minerals within the cement-stabilized soils were fully considered in the current thermodynamic model. To simplify the analyses, montmorillonite and C\({}_{3}\)S were used to represent the reactants in the mineralogy of the raw materials, CSH and AFt were used to represent the cement hydrates in the crystallinity and fractions of the hydrates and natrolite was used to represent the pozzolanic products since Na\({}^{+}\) is the most abundant of the exchangeable cations in soil. The lg_IAP_ values for the reactants montmorillonite and C\({}_{3}\)S, from 5 h to 672 h, are summarized in Figure 3a,b, respectively. The _SI_ values for the products CSH, AFt and natrolite are summarized in Figure 3c-e, respectively. Figure 3 shows that the development patterns of the reactant dissolution and product formation over the curing period were similar to those of the pore solution (as shown in Table 4), which confirmed that the chemical kinetics in the cement-stabilized soils was dominated by the dissolution and precipitation processes [21]. Due to the differences in solubility and mass fractions, the development patterns of the minerals that related to the pozzolanic reaction were significantly different from those relating to cement hydration. As montmorillonite had a lower solubility than C3S, its lg_IAP_ values were lower than those of C3S; however, as montmorillonite was the most abundant mineral in the raw materials, its lg_IAP_ values at 672 h were still higher than those at 5 h, while the lg_IAP_ values of C3S dropped below the initial values as early as after 168 h. The _SI_ development of CSH, AFt and matrolite over the curing period indicated that the cement hydrates formed intensively before 10 h and turned out to be slowly formed or unstable in the long term, while the pozzolanic products formed stably and significantly affected the long-term performances of the cement-stabilized soils. Meanwhile, out of the investigated reaction products, only CSH produced a consistent pattern for UCS with respect to the type and dose of the admixtures. These results agreed well with the widely accepted knowledge [41] that the dominant chemical kinetics of the performance development of cement-stabilized soils are cement hydration, followed by the pozzolanic reaction of the soil minerals and that the crucial product that influences this performance is CSH. In addition, the change timing of the dominant chemical kinetics in the plain cement-stabilized soils was at around 168 h, which coincided with the first occurrences of CSH equilibrium and AFt undersaturation. Regarding the individual effects of JA on the investigated minerals, the dose of 0.8% promoted the dissolution of C3S and montmorillonite and affected the saturation levels of  
Figure 3: The thermodynamic calculations for the investigated minerals: (**a**) C3S; (**b**) montmorillonite; (**c**) C(N)ASH; (**d**) AFt; (**e**) natrolite. CSH, AFt and natrolite to different magnitudes. The CSH formation was prolonged to after 672 h, the AFt dissolution after 168 h was inhibited and the timing of the highest _SI_ value of natrolite was delayed to 24 h. When the JA dose was increased to 1.2%, the montmorillonite dissolution and natrolite supersaturation were further improved. While the C\({}_{3}\)S dissolution was obviously inhibited, the first occurrence of CSH undersaturation was brought forward to 168 h and the AFt was lowered to an unsaturated level within the whole timeframe. Combining the analyses of the UCS and the pore solution, the modification effects of JA on the cement-stabilized soils were mainly derived from the dissolution process of the JA itself, which altered the alkalinity of the pore solution and affected the dissolution of the raw reactants within the system.