To fully describe the roughness of coarse aggregate

the height difference correlation function was introduced to characterize the surface texture of coarse aggregate with multi-parameters. First

the needle profiler was applied to obtain the texture profile curve of the aggregate surface and eliminate the error in data acquisition. Then

the height difference correlation function of the coarse aggregate was calculated

and the curve was fitted with piecewise fitting. The self-similar feature parameters (D

ξ∥

ξSymbol^A@) of the surface texture curve were calculated as evaluation indexes to analyze the roughness of the surface texture of the coarse aggregate. Results show that the surface texture of the coarse aggregate had two sections of variable dimension within a certain range

and the scale boundary between the micro texture and the macro texture was 100-200 μm. The fractal dimension D1 of the macro texture of different aggregates was about 1.3

and the fractal dimension D2 of the micro texture was about 1.05

which revealed that the fractal dimension was insensitive to roughness. The horizontal cutoff wavelength ξ∥ and the amplitude expectation value ξSymbol^A@ reflected the expected values of the horizontal wavelength and the vertical amplitude of the micro-convex surface of the coarse aggregate

respectively. The horizontal cutoff wavelength ξ∥ reflected the size of the largest microbump. The dolomite and the diorite were smaller

while the granite with larger crystal structure had a maximum value. The amplitude expectation value ξSymbol^A@ was diorite

yellow sandstone

granite 1

diabase

granite 2

and dolomite in descending order

which was in line with the actual situation. The amplitude expectation value could quantitatively describe the overall roughness of the aggregate. The self-similar feature parameters could fully describe the roughness of the surface texture of the coarse aggregate.