Super-fine stainless wires enabled multifunctional and smart reactive powder concrete

Super-fine stainless wire (SSW) with excellent mechanical, electrical, thermal and electromagnetic characteristics can form a widely-distributed reinforcing network in reactive powder concrete (RPC) at low dosage, thus endowing RPC with desired mechanical performance and functional property. The multi-functional and smart properties of SSW reinforced RPC were investigated in this paper. The research results indicated that the flexural strength, compressive strength and flexural toughness of RPC reinforced with 1.5% SSWs are 31.9%, 41.2% and 114.4% higher than that of RPC without SSW. The electrical resistivity of composites is reduced by six orders of magnitude and the electrochemical impedance spectroscopy only shows small flat arcs in the first quadrant. SSW reinforced RPC exhibits stable piezoresistive response under cyclic compressive loading. Meanwhile, the gauge factor of 1.5% SSWs reinforced RPC under monotonic compressive loading can reach 153.9. The addition of 1.5% SSWs leads to 19.9% increase in damping ratio of RPC as well as 202.9% increase for electromagnetic wave shielding efficiency at the frequency of 4 GHz. The electromagnetic wave absorbing property of RPC reinforced with 1.5% SSWs exceeds 125.0% of that of RPC without SSW in the frequency range of 17–18 GHz. The addition of SSW can effectively increase the thermal conductivity and wear resistance of RPC. SSW reinforced RPC has great potential for developing multi-functional and smart infrastructures, thus improving their safety, longevity and function.