Shear behavior at the interface: experimental study on the roles of sand grain size and concrete surface roughness
نویسندگان
1 Department of Civil Engineering, Gonbad Kavoos Branch, Islamic Azad University, Gonbad Kavoos, Iran.
2 Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.
3 Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.
doi
10.22059/ijmge.2025.368129.595122چکیده
This study provides novel insights into the shear resistance behavior at the concrete-sand interface, focusing on the combined effects of sand grain size, concrete surface roughness, and soil relative density. While individual parameters have been explored in previous research, this work systematically examines their interactions to better understand interface shear strength. A series of large direct shear tests was conducted on concrete-sand samples with varying surface roughness values (Rmax = 0, 0.2, 4, and 8 mm) and granular materials with different mean particle sizes (D50 = 0.25 mm, 0.8 mm, and 2 mm). The granular materials were compacted to different relative densities (Dr = 30%, 60%, and 90%). The results revealed that increasing relative density from 30% to 60%, and from 30% to 90%, led to substantial rises in interface friction (approximately 105% and 306%, respectively). Coarser sand exhibited a more pronounced increase in interface friction angle than finer sand. Furthermore, increasing concrete surface roughness from 2 mm to 8 mm resulted in a 27% increase in the friction angle. These findings highlight the significant role of these parameters in governing the interaction between concrete and granular soil, offering valuable insights for applications in civil engineering.
