Aerosol generation in compressive concrete fragmentation

In this study, the macro-, micro-, and nano- scale fragmentation of concrete was studied as a function of different admixtures and inclusions. Fragments were generated by rapidly loading concrete test specimens under 1D axial compression at a constant strain rate and sampling the generated airborne dust during the impact event. The results of this study showed that the aerosol fragment size distributions generated by rapid fragmentation of concrete follow a bi-modal distribution tied to microstructural features of the concrete mix. This experimental behavior is well described by introducing additional length scales in Gilvarry's derivation of the Rosin-Rammler-Sperlin-Bennet (RRSB) size distribution. On this basis, it is proposed that no new fragmentation theory is needed to describe aerosol particles if concrete fragmentation is regarded as a composite material explicitly considering microstructural features which create stress concentrations on the microscale. By identifying a direct link between microstructural features and aerosol distributions, it will be possible to design concrete microstructures to limit aerosol exposure during dynamic failures such as structural collapse.