The efficiency of mechanical concrete comminution

The paper reports about the comminution of cementitious composites in a laboratory jaw breaker. Six different concrete types, two mixtures of hardened cement paste, and one mortar sample are investigated. The efficiency of the breaking process is calculated based on a non-linear fracture approach. The efficiency η is the ratio between net energy delivered by the crusher and the fracture energy dissipated in the materials during the fragmentation process. Typical efficiency values between 0.03<η<0.19 are estimated. However, efficiency increases as the fracture energy of the material increases and brittleness decreases. Jaw breakers are efficient for low-brittle materials. It is suggested to use the approach developed in the paper for estimating the efficiency of rock comminution processes.