Abstract: In view of the difficulty of predicting macroscopic mechanical properties of concrete caused by material heterogeneity,size effect and rate sensitivity,this paper aims to establish a practical analysis model of concrete strength considering the effects of material ratio,structure size and loading rate.The tensile strength is taken as the main research object.Firstly,the basic expression of nominal dynamic tensile strength of concrete is derived and established.Secondly,based on the mesoscale numerical simulation method and size effect numerical tests,the determination methods for parameters B and D₀ in the classical Type-2 size effect model are analyzed and determined.Furthermore,based on the numerical test results,the effectiveness of the proposed model is verified from three aspects:aggregate size effect,structure size effect and load strain rate effect.Finally,based on the relevant test data of concrete dynamic tensile strength,the rationality of the prediction results of the model is further verified.The results show that:(1) Material parameter B decreases monotonically with the increase of interface strength,and material parameter D₀ increases first and then decreases with the increase of interface strength;(2) When the interfacial strength is high,the splitting tensile strength of concrete increases with the increase of the maximum aggregate size,while when the interfacial strength is low,the splitting tensile strength of concrete decreases with the increase of the maximum aggregate size.(3) The splitting tensile strength of concrete gradually increases with the increase of load strain rate,and considering the inertia effect,the larger the structure size,the greater the improvement range;(4) When the load strain rate is low,the splitting tensile strength of concrete decreases with the increase of structure size,and when the load strain rate is high,the splitting tensile strength of concrete increases with the increase of structure size.