Experimental and numerical investigation on fracture characteristics of self-compacting concrete mixed with waste rubber particles

Replacing natural aggregates in concrete with waste rubber particles is an effective method to solve environmental problems, but the use of rubber due to its unknown characteristics can change the fracture performance and cracking behavior of self-compacting concrete. Hence, through experimental analysis and discrete element method (DEM) simulation, this paper aims to investigate the influence of different rubber contents (0%, 10%, 20% and 30%) on fracture characteristics of self-compacting concrete. Compared with natural river sand, rubber particles have more flexible structure and stronger deformation ability, and these unique properties enhance the bridging effect between matrices and weaken the stress concentration at the crack tip, which shows that the fracture parameters of self-compacting rubberized concrete (SCRC) increase linearly with the increase of rubber content, and this linear growth rate will increase with the increase of beam size. Moreover, the addition of rubber particles absorbs most of the energy generated in the fracture process, which significantly enhances the anticracking ability of SCRC, and this ability to prevent crack propagation will be enhanced with the increase of rubber content, which is manifested by the significant decrease of acoustic emission (AE) activity. Based on the shapes of real aggregates and rubber particles, a universal DEM fracture prediction model for SCRC is established, which can better describe the fracture response of SCRC with different rubber contents and sizes under flexural loads. The evaluation of economic and environmental benefits indicates that adding rubber particles into self-compacting concrete can not only save costs, but also produce considerable environmental benefits.