## 3 Results
### Assessment of the Mechanical Behavior (Strength and Stiffness) of Novel Geomaterials
Through this comparison, the study seeks to validate the applicability of the index as an effective predictive tool for estimating the mechanical properties of mixtures containing unconventional geomaterials. Additionally, this approach enables the evaluation of stabilization efficiency across different formulations and contributes to establishing rational guidelines for optimizing binder dosages in sustainable soil improvement projects. Figure 12 presents the results of the fitted dosage curve for the unconfined compressive strength of the eight mixtures. The dosage curves fitted for each mixture revealed distinct trends based on the type of stabilizing material. For all mixtures incorporating construction residues (CLW, GY, and GG), a unified exponent of x = 0.28 provided consistent and high-quality fits across the board, with coefficients of determination (\(R^{2}\)) ranging from 0.86 to 0.97. This consistency suggests that the porosity and binder content exerted a relatively balanced and predictable influence on compressive strength, enabling the use of a common power-law exponent for all residue-based formulations. Among these, GY-treated mixtures achieved the highest correlation (\(R^{2}\) = 0.97 for 20% GY), highlighting its superior performance in strength development and homogeneity of response. As described by [PERSON] et al. [43,44], these empirical curves reflect the combined contribution of the cemented phase and the soil matrix, with the cementation bonds being the dominant factor influencing the scaling constant A. In contrast, mixtures treated with XG and XG-PPF exhibited fundamentally different behavior. The best-fitting dosage curves required significantly lower exponents, with x = 0.02 for XG and x = 0.03 for XG-PPF, indicating that porosity plays a far more dominant role in strength development for biopolymer-based mixtures. Additionally, the markedly higher values of the constant A (on the order of 10\({}^{10}\)-10\({}^{11}\)) further reflect the sensitivity of these systems to small changes in internal structure. As proposed by [PERSON] et al. [45], the parameter A in such mixtures may also encapsulate the combined effects of the fiber reinforcement and the frictional resistance of the soil matrix, particularly in formulations where no traditional cement is present. Despite achieving high determination coefficients (\(R^{2}>0.94\)), the need to use distinct exponents for XG-based formulations suggests that a single, unified adjustment--such as the one applied to the residue-based mixtures--is not suitable for biopolymer-stabilized soils. The stiffness results (G\({}_{0}\)) (Figure 13) revealed similar behavioral trends to those observed in the compressive strength analysis, further confirming the reliability of the porosity/binder index as a predictive tool. For the mixtures containing construction residues, the use of a unified exponent of x = 0.28 again produced strong correlations, with \(R^{2}\) values ranging from 0.92 to 0.98. The highest stiffness was achieved with 20% GY (\(R^{2}\) = 0.92) and 20% GG (\(R^{2}\) = 0.98), while CLW-based mixtures also showed good fit, especially at 30% content. These results demonstrate that the porosity and binder content jointly control the mechanical response in terms of both strength and stiffness. In contrast, XG and XG-PPF mixtures required considerably lower exponents (x = 0.02 and x = 0.03, respectively), consistent with their compressive strength behavior. Moreover, the values of parameter A remained significantly higher, reaffirming the sensitivity of biopolymer-treated soils to small variations in void structure and internal bonding. These findings reinforce the  
Figure 12: Influence of the porosity/cement ratio on the unconfined compressive strength of the novel geomaterials after 28 days of curing. premise put forward by [PERSON] et al. (2014, 2015) and [PERSON] et al. (2016), who emphasized that both the C and x exponents are strongly dependent on the nature of the soil matrix and the type of bonding developed in the mixture.