Quantitative analysis of morphological features of recycled asphalt pavement and natural coarse aggregates using aggregate image measurement system

Recycled asphalt pavement (RAP) has application not only in asphalt pavement recycling technology but also in cement concrete as coarse aggregates. The morphological features greatly impact workability and mechanical properties of cement concrete. This paper mainly uses the AIMS system to quantitatively measure the morphological feature of aggregates, including natural coarse aggregates (CA), RAP with different asphalt contents and post-combustion RAP. Morphological feature including angularity, sphericity, texture value, and fractal dimension. Additionally, statistical analysis was conducted on the morphological features, exploring the differences in these features between RAP and CA. RAP has lower angularity, higher sphericity, and lower texture value compared to CA. Compared to pre-combustion RAP1 and RAP2, average angularity and texture value of post-combustion RAP increased in the 4.75–16 mm diameter range. The average sphericity of post-combustion RAP1 and RAP2 decreased with diameter range 4.75–16 mm. Compared to CA, the fractal dimension of 4.75–9.5 mm diameter RAP was higher, indicating that the shape of 4.75–9.5 mm diameter RAP is more complex. The type of aggregates significantly affects texture value. The diameter of coarse aggregates has small affects the angularity and texture value. Analyzing the correlation between morphological feature indicators in RAP with different asphalt contents and CA contributes to better understanding of aggregate shape characteristics. This contributes to their highly efficient and high-quality utilization. • AIMS used to quantitatively measure the morphological feature of RAP and CA. • Two-way ANOVA used to analyze aggregate types and diameters impact on morphological feature. • Analyzing the correlation between morphological feature indicators in RAP and CA.