Study on the influence of waste glass powder particle size and content on bond-slip performance of reinforced concrete

To investigate the influence of waste glass powder's particle size and content on the bond–slip behavior of reinforced concrete, this study integrates laboratory experiments with theoretical analysis to examine the effects of varying waste glass powder particle sizes (<20, 20–75, 75–150 μm) and replacement contents (10%, 20%, 30%) on bond–slip performance and failure modes. The research clarifies the mechanism by which waste glass powder affects bond–slip behavior and establishes a bond–slip constitutive model that accounts for the coupling effects of particle size and content. The results indicate that at the same replacement level, smaller waste glass powder particles exhibit a larger specific surface area and higher reactivity. This facilitates the formation of more calcium silicate hydrate gel through pozzolanic reactions, thereby enhancing concrete's compactness and bond strength. Under identical particle size conditions, bond strength first increases and then decreases with increasing waste glass powder content, peaking at a 10% replacement content. Compared with reference specimens without waste glass powder, this optimal replacement content enhances bond strength by 5.3%. An appropriate amount of waste glass powder can effectively fill concrete pores and improve the uniformity of stress distribution, with specimens exhibiting pull-out failure modes. However, excessive incorporation of waste glass powder may induce alkali–silica reactions, generating expansive gels that render concrete more prone to splitting failure. The proposed bond–slip model shows good agreement with the experimental results, accurately characterizing the bond–slip performance of waste glass powder-modified reinforced concrete under the combined influence of different particle sizes and replacement contents.