Abstract: To investigate the enhancement mechanism of basalt fiber on the mechanical properties of concrete,this study
examined the effects of different basalt fiber volume fractions on the uniaxial compressive failure characteristics,strength properties,
and toughness of concrete through uniaxial compression tests on cubic specimens. The energy-based working mechanism
of basalt fiber during the failure process was also analyzed. Results indicated that the addition of basalt fiber effectively retarded
crack propagation and reduced damage degree of specimens. With increasing fiber volume fraction,the uniaxial compressive
strength of concrete first increased and then decreased,while the corresponding peak displacement showed an increasing trend
with gradually reduced growth rate. The compressive toughness of specimens was significantly improved by fiber reinforcement,
demonstrating a continuously ascending tendency with increasing fiber content. The energy evolution during uniaxial compression
failure of basalt fiber-reinforced concrete specimens could be divided into four distinct stages:compaction phase,energy
storage phase,localized damage phase,and accelerated elastic energy release phase. The incorporation of basalt fibers can significantly
reduce the release rate of elastic energy and increase the energy storage limit of the concrete,manifested as an increase
in the energy demarcation point,thereby enhancing the deformation capacity of the specimens.

Key words: basalt fiber,concrete,compressive strength,tenacity,energy analysis