Effect of particle shape on mechanical properties of recycled concrete particles under the critical state soil mechanics

Recycled concrete particles, a primary component of construction and demolition waste (CDW), significantly contributes to the shear strength of CDW. The influence of particle shape on the mechanical properties of recycled concrete is of importance. This paper constructs four numerical simulation models with varying degrees of sphericity using discrete element simulation. The critical state line (CSL) of the samples is determined through triaxial shearing simulation tests, in conjunction with critical state soil mechanics analysis. The results indicate that particle sphericity markedly affects the macroscopic mechanical properties of recycled concrete particles. With the increase in particle sphericity under higher confining pressure, the deviatoric stress is decreased. Additionally, the cohesion of the samples rises with increasing sphericity, whereas the friction angle decreases. It is worth noting that with the increase of sphericity, the CSL slope of the sample shows a downward trend on both the q-p' and e-log p' planes. • Effect of particle sphericity on mechanical properties of recycled concrete particle was studied. • The slope of the Critical State Line(CSL) on the q-p' and e-log p' planes always decreases as particle sphericity increases. • The increase of particle sphericity results in the increase of cohesion and the decrease of internal friction angle.