In order to promote the wide application of reactive powder concrete (RPC) in practical engineering. In this paper, RPC was prepared using conventional and economical natural river sand instead of quartz sand and economical and environmentally friendly basalt fiber (BF) instead of steel fiber, and the macroscopic properties of basalt fiber reactive powder concrete (BFRPC) with different fiber content, such as flowability, failure mode, compressive strength and splitting tensile strength were studied, and the strength calculation formula of BFRPC was established based on the mechanical property results. The microscopic morphology and structure of BFRPC were characterized by scanning electron microscope (SEM) and Image Pro Plus (IPP) image processing software. The results show that BF has a small effect on the compressive strength of RPC, while it has a significant increase on the splitting tensile strength. When BF content is at 2 kg/m³, the 28-day compressive strength reaches 95.2 MPa and splitting tensile strength reaches 7.78 MPa. Compared with the RPC with BF of 0 kg/m³, the BFRPC shows an improvement in its 28-day compressive strength by 25.70% and an increase in its splitting tensile strength by 83.92%. According to the microscopic analysis, reasonable fiber content can optimize the internal microstructure of BFRPC, but excessive BF content will produce agglomeration and overlap, resulting in strength loss. Based on the gray correlation analysis method, it was concluded that the particle area ratio and pore fraction dimension were the most correlated with the mechanical properties of BFRPC. In addition, the feasibility and applicability of the BFRPC strength calculation formula were summarized. This research results of this paper provides a valuable reference for the further research and promotion of BFRPC.

To address the susceptibility of traditional concrete to explosive spalling and the lack of in situ damage-monitoring methods at high temperatures, in this study, a novel self-sensing, high-temperature-resistant Engineered Cementitious Composite (ECC) was developed. The matrix contains eco-friendly glass sand reinforced with a hybrid system of polypropylene fibers (PPFs) and carbon fibers (CFs). The evolution of mechanical properties and the multimodal self-sensing characteristics of the ECC were systematically investigated following thermal treatment from 20 °C to 800 °C. The results indicate that the hybrid system exhibits a significant synergistic effect: through PFFs’ pore-forming mechanism, internal vapor pressure is effectively released to mitigate spalling, while CFs provide residual strength compensation. Mechanically, the compressive strength increased by 51.32% (0.9% CF + 1.0% PPF) at 400 °C compared to ambient temperature, attributed to high-temperature-activated secondary hydration. Regarding self-sensing, the composite containing 1.1% CF and 1.5% PPF displayed superior thermosensitivity during heating (resistivity reduction of 49.1%), indicating potential for early fire warnings. Notably, pressure sensitivity was enhanced after high-temperature exposure, with the 0.7% CF + 0.5% PPF group achieving a Fractional Change in Resistivity of 31.1% at 600 °C. Conversely, flexural sensitivity presented a “thermally induced attenuation effect” primarily attributed to high-temperature-induced interfacial weakening. This study confirms that the “pore-formation” mechanism, combined with the reconstruction of the conductive network, governs the material’s macroscopic properties, providing a theoretical basis for green, intelligent, and fire-safe infrastructure.