Size effect difference between uniaxial and splitting tensile strength of recycled aggregate concrete considering the maximum aggregate size: Meso-simulation

To study the influence law of maximum aggregate particle size ( d max ) on the uniaxial and split tensile damage behavior, strength , and size effect of recycled aggregate concrete (RAC), a mesoscale random aggregate model was established based on continuous grading, and numerical simulation studies were carried out to investigate the mechanical behavior of RAC with different model cross-section sizes ( D ) and d max , and to establish the strength relational equations between the two tensile modes. The results show that the uniaxial and split tensile strengths under the same d max decrease with the increase of D , and the highest decrease reaches 29.58 % and 31.27 %, respectively. The impact of increasing d max on the tensile strength is categorized into the direct effects on the strength and the indirect effects of weakening the size effect, and the tortuosity of the tensile cracks of the specimen increases with the increment of d max . The uniaxial tensile strength of the specimens at the same D and d max is always slightly less than the split tensile. Meanwhile, based on the systematic analysis of the behavior of the size effect in this study, it is verified in comparison with the size effect theory proposed by Weibull, Bažant, and Carpinteri, which proved that the data within the scope of this study can better apply the above theory. Based on the Bažant Type-2 size effect law, a size effect equation that considers the impact of d max is also developed, and the rationality of the equation is verified. This theoretical equation may quantitatively predict the correlation for the tensile strength and size of RAC based on D and d max . ● The effect of maximum aggregate particle size on RAC tensile strength was investigated. ● Size effects of uniaxial and splitting tensile strength of recycled aggregate concrete were simulated. ● Concrete crack tortuosity increases as the maximum aggregate particle size increases. ● The theoretical equation may predict the correlation for the tensile strength and size.