US Patent 10034418 Concrete mix for shotcrete applications for electromagnetic shielding

Conductive concrete mixtures for shotcrete applications are described that are configured to provide varied EM shielding and reflect and/or absorb, for instance, EM waves propagating through the conductive concrete mixture, while providing flowability (e.g., fluidity) for shotcrete applications. The conductive concrete mixtures include cement, aggregate, water, metallic conductive material, and conductive carbon particles and magnetic material. The metallic conductive material may include steel fibers and/or shavings having sizes suitable for application through shotcrete nozzles/applicators, and the magnetic material may include a taconite aggregate, such as taconite sand.