A novel thermal conductivity prediction model was developed to address the complex influence of pore structure in porous materials. This model incorporates pore size (d) and a pore distribution parameter (t) to calculate the material’s thermal conductivity. To validate the model’s accuracy, geopolymer foamed concrete (GFC) samples with varying pore structures were fabricated. These utilized ground granulated blast furnace slag (GGBS) as the precursor, a mixed solution of sodium hydroxide (NaOH) and sodium silicate as the alkaline activator, and sodium stearate (NaSt), hydroxypropyl methylcellulose (HPMC), and sodium carboxymethyl cellulose (CMC-Na) as foam stabilizers. Conventional pore size characterization techniques exhibit limitations; consequently, this research implements a high-fidelity machine vision-driven image analysis methodology. Pore size measurement is achieved through a combined technical approach involving equivalent diameter modeling and morphological optimization. The feasibility of the proposed theory is validated by our experimental data and data from previous literature, with the error between experimental and theoretical values maintained within 5%. The value of t increases with increasing porosity and increasing disorder in pore distribution. Based on the experimental data obtained in this study and the research data from previous scholars’ studies, the t value for porous materials can be categorized according to porosity: when porosity is approximately 30%, t ≈ 0.9; when porosity is 55~65%, t ranges from 1.2 to 1.3; and when porosity is approximately 80%, t ranges from 1.9 to 2.2.

Based on the dual requirements of building energy efficiency and construction industrialization, along with the development of high-strength, high thermal resistance (low thermal conductivity) foamed concrete (HLFC), this study proposes a new prefabricated high-strength foamed concrete thermal self-insulating shear wall system (called HFSW shear wall) suitable for multi-story buildings, which could address the core shortcomings of existing organic insulation materials in buildings, such as poor fire resistance and short life cycles. Concerning the research gap in the flexural performance of this wall type, this study conducted seismic tests on two full-scale wall models and systematically analyzed the fundamental performance parameters under quasi-static loading, including bending failure phenomena, load-bearing capacity, stiffness degradation, energy dissipation capacity, and ductility. The results show that HFSW walls with large shear span ratios generally exhibit typical bending failure characteristics. However, due to the relatively low material strength, extensive development of shear and flexural–shear cracks occurs, leading to minimal differences in typical seismic performance indicators compared to shear-dominated failure scenarios in traditional shear walls (indicating significant flexural–shear coupling effects). Finally, a finite element model was used to simulate the wall capacity under various parameters, including axial compression ratio, wall thickness, and longitudinal reinforcement in edge columns. Based on the validated and calibrated finite element results, and in accordance with the wall failure mode as well as the load transfer mechanism, a calculation model for the flexural strength of HFSW shear walls was established to guide design and engineering application, achieving a theoretical calculation accuracy of 0.97. The research findings provide meaningful guidance for the design and application of this wall system.