Abstract: In this study, the digital image processing technology was used to characterize the particle shape of the recycled brick concrete coarse aggregate. The distribution of characteristic parameters such as height width ratio, roundness and compact factor of each component was also analyzed. The experimental results show that the aggregate material is accurately identified through the color analysis, and the height width ratio, roundness and compact factor of the aggregate particles obtained based on the identification results have similar distribution rules. Among the four components of brick, stone, wood and ceramics, brick and stone account for a relatively larger proportion, and their characteristic parameters are also relatively similar, with less needle-like particles and better roundness, while wood aggregate is mostly needle-like particles with a larger height width ratio. Ceramics has the largest area and perimeter due to its higher strength. In addition, the gradation distribution of the brick and stone aggregates is basically a normal distribution, which can be mixed to form a well-graded aggregate. The research results are helpful to reveal the particle morphology characteristics of the recycled brick concrete coarse aggregate, and promote the research and application of the recycled brick concrete coarse aggregate.

Key words: recycled brick concrete coarse aggregate, morphological characterization, digital image processing, height width ratio, roundness, compact factor