The creep acoustic emission (AE) location tests of red sandstone were carried out

and the evolution of AE source along loading direction and perpendicular to loading direction was analyzed. On this basis

the fractal characteristics of source zi value and ri value were studied with fixed time window and time step. The results show that when the creep stress is equal to or greater than the damage stress

the spatio-temporal evolution law of AE source reflects the process of micro-cracks initiation

nucleation

expansion and coalescence. The initiation of micro-cracks mainly occurs in the stage of decelerating creep. During this process

the micro-cracks evolve from the end surfaces and the outer wall to the center of the specimen along the loading direction and the vertical loading direction

and the fractal dimension of zi values and ri values generally decrease. The nucleation process of the micro-cracks appears in the stage of steady creep

and nucleation area locates in the center of the specimen. Then

with the increase of the creep time

the micro-cracks step into the expansion stage

in which the evolution of the micro-cracks is manifested as the expansion process from the center of the specimen to the direction of the end surface and the outer wall

and the fractal dimensions of the corresponding zi values and ri values are at low levels

which can be used as a marker for the process of micro-cracks nucleation and expansion. The coalescence of micro-cracks occurs in the accelerated creep stage. During this process

the micro-cracks are mainly distributed in the axial upper and lower part of the specimen along the loading direction

while in the vertical loading direction

the micro-cracks are distributed all over the radius of the specimen. However

the fractal dimension of source zi value and ri value both increase slightly with the increase of creep time

which can be used as a symbol of micro-cracks coalescing process. The findings in study can provide theoretical and experimental support for exploring rock creep micro-mechanism and creep failure prediction method.