## 5 Conclusions  
In this paper, based on uniaxial compression experiments and nuclear magnetic resonance (NMR) experiments, we quantitatively analyzed the damage mechanisms and progression of microwaves on basalt from both macroscopic and microscopic perspectives:  
(1) Through uniaxial loading and unloading experiments, we demonstrated that the energy storage capacity of basalt specimens before peak stress diminishes with increased microwave radiation power and irradiation time. As a result, a larger proportion of the input energy from the testing machine is converted into dissipated energy, leading to more extensive damage to the specimens.  
(2) Under 3 kW of microwave radiation, the damage coefficient F_D of the specimen after 30 s of irradiation is only 29.89% of that after 60 s, while the damage coefficient after 90 s reaches 85.25% of that after 120 s. Similarly, under 6 kW of microwave radiation, the damage coefficient after 30 s is 36.93% of that after 60 s, and the damage coefficient  
Figure 15: Schematic diagram of the mechanism of basalt damage after microwave treatment.  
after 90 s reaches 94.51% of that after 120 s. These findings highlight the progressive nature of damage accumulation with longer irradiation times, with higher power settings accelerating the damage process. Moreover, the extent of damage follows a pattern where the rate of damage initially increases and then decreases as radiation time is extended. In practical rock-breaking engineering applications, it is advisable that the exposure duration for 3 kW and 6 kW microwave radiation should not exceed 90 s; otherwise, the project may become economically unfeasible.  
(3) In the uniaxial loading experiments, we incorporated acoustic emission (AE) testing. The results revealed that the AE counts of basalt specimens increased with prolonged microwave radiation. Simultaneously, the ratio of shear cracks to the total number of cracks within the specimens increased with irradiation time.  
(4) Using nuclear magnetic resonance (NMR) to analyze porosity and pore distribution, we observed that microwave treatment significantly increases the porosity of basalt, indicating the expansion of existing pores and the formation of new fractures. Fractal analysis of the pores via linear regression suggests that the fractal dimension of macropores increases with extended microwave exposure. This indicates that microwave radiation not only enlarges existing pores but also encourages the formation of new ones, resulting in a more complex pore structure within the basalt.  
T.Y.: Conceptualization, Data curation, Formal analysis, Investigation, Funding acquisition, Resources, Writing--original draft, Writing--review and editing. J.W.: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Validation, Writing--original draft, Writing--review and editing. J.M.: Investigation, Validation. J.L.: Investigation, Validation. H.D.: Investigation, Validation. All authors have read and agreed to the published version of the manuscript.  
This work was financially supported by the Natural Science Foundation of Hunan Province (2023 JJ30662) and Fundamental Research Funds for the Central Universities of Central South University (2024 ZZTS0701). We also thank the anonymous reviewers for their valuable comments and suggestions for improving this manuscript.  
The data presented in this study are available on request from the corresponding author.  
We declare that we have no financial or personal relationships with other people or organizations that could inappropriately influence our work. There are no professional or other personal interests of any nature or kind in any product, service, and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled.