Characterization of nano particles released during asphalt and concrete laboratory activities

Although nanomaterials possess new properties and their industrial application generates promising opportunities in construction, they also present new risks and uncertainties. To quantify the level of risks associated with engineered nanomaterials, research needs to first quantify the level of nanoparticles exposure encountered in different construction activities. Therefore, the objective of this study is to evaluate the potential inhalation exposure risk associated with Hot-Mix Asphalt (HMA) and Portland Cement Concrete (PCC) preparation activities in the laboratory. To achieve this objective, the number concentration, size distribution, surface area, and mass concentrationwere measured for different activities including dry mixing, wet mixing, pouring, and compaction in an asphalt and concrete laboratory using a Scanning Mobility Particle Sizer (SMPS). Results showed that more than 70% of the particles in the concrete preparation activities were ultrafine particles. In addition, workers in the concrete laboratory were exposed to relatively higher ultrafine particles concentrations than workers in the asphalt laboratory. The majority of the total particle number (49%) released during concrete laboratory activities was in the lowest size category, between 10-30 nm in diameter.Based on the results of this study, further research is needed to understand the negative effects of nanoparticles on the health of workers.