Effect of aggregate content on the CFRP-concrete effective bond length: An experimental and analytical study

Abstract

Despite the wide range of proposed models in construction codes for estimating the carbon fiber reinforced polymer (CFRP)-concrete effective bond length, no attention has yet been given in the codes regarding the effect of aggregate content on effective bond length. The current study investigated the above-mentioned issues with varying volumes of coarse aggregates based on the concept of ‘sand ratio’ defined as the ratio of fine aggregate volume-to-total aggregates’ volume in concrete. For this purpose, 52 single-lap shear tests were conducted in two main groups of 23 and 35 MPa compressive strengths of concrete. Analytical and experimental results revealed that the effective bond length increased by 54% by increasing the sand ratio from 0.34 to 0.70 for the first group. However, the effective bond length demonstrated a 26% reduction by increasing the sand ratio from 0.70 to 1.00. Regarding the second group, the effective bond length increased by 45% by increasing the sand ratio from 0.29 to 0.62, while the effective bond length represented a 40% decrease by increasing the sand ratio from 0.62 to 1.00. Finally, the results indicated the necessity of correction factors in code models to explain the sand ratio effect. Such correction factors were extracted to be applied to the code models.