YAN C B, FENG R L, LI R,et al.Morphological characterization of recycled coarse aggregates and their effects on concrete properties[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(4):170-179.

doi:10.16186/j.cnki.1673-9787.2025070019

Received:2025/07/18

Revised:2025/10/16

Published:2026/06/17

Morphological characterization of recycled coarse aggregates and their effects on concrete properties

Yan Changbin1, Feng Renlong1, Li Rui1, Zhao Hailei2, Yang Zhenxing2, Du Pengzhao3, Du Weichang3

1.School of  Civil Engineering， Zhengzhou University， Zhengzhou  450001， Henan， China;2.State Key Laboratory of Shield Machine and Boring Technology， Zhengzhou  450001， Henan， China;3.Yellow River Engineering Consulting Co.， Ltd.， Zhengzhou  450003， Henan， China

Abstract: Objectives To address the limited particle size range in studies on the morphology of recycled coarse aggregates and the insufficient research on their effects on concrete properties.  Methods 3D laser scanning and image processing techniques were used to analyze the morphology distribution patterns of sphericity， convexity， roughness， and 3D fractal dimension of recycled coarse aggregates in the 4.75-31.5 mm range， and to investigate their effects on the workability and mechanical properties of concrete.  Results The results show that： 1. The greatest heterogeneity in sphericity and roughness was observed in recycled coarse aggregates of 4.75~9.5 mm， whereas convexity heterogeneity peaked in the 9.5~16 mm range. Aggregates of 26.5~`31.5 mm exhibited the lowest heterogeneity in sphericity， convexity， and roughness. 2. With increasing particle size， the average sphericity remained largely unchanged； convexity first decreased and then increased； roughness first decreased， then increased， and finally decreased again； the 3D fractal dimension gradually decreased. 3. Recycled coarse aggregates in all particle size intervals showed strong fractal characteristics， with a 3D fractal dimension of 2.010 for the 4.75–31.5 mm interval. 4. A decrease in the proportion of spheroidal and irregular aggregates reduced concrete slump， while compressive and splitting tensile strengths initially increased and then decreased. 5.  Among the morphological parameters， 3D fractal dimension and sphericity had the greatest influence on workability； 3D fractal dimension most affected compressive strength， and sphericity most affected splitting tensile strength.  Conclusions Sphericity is largely independent of particle size， whereas convexity， roughness， and 3D fractal dimension vary with particle size. These morphological parameters have varying degrees of influence on the workability and mechanical properties of concrete.

Key words:recycled coarse aggregate;3D laser scanning; concrete; sphericity; convexity; roughness; fractal; dimension