Fracture and self-sensing characteristics of super-fine stainless wire reinforced reactive powder concrete

Abstract

Super-fine stainless wire (SSW) can not only form widely distributed enhancing, toughening and conductive network in reactive powder concrete (RPC) at low dosage level, but also improve weak interface area and refine cracks due to its micron scale diameter and large specific surface. In addition, the crack resistance zone generated by SSWs and RPC matrix together has potential to further enhance the fracture properties of composites. Therefore, fracture and self-sensing characteristics of SSW reinforced RPC composites were investigated in this paper. Experimental results indicated that adding 1.5 vol. % of SSW leads to 183.1% increase in the initial cracking load of RPC specimens under three-point bending load. Based on two parameter fracture model calculations, an increase of 203.4% in fracture toughness as well as an increase of 113.3% in crack tip opening displacement of the composites reinforced with 1.5% SSWs are achieved. According to double-K fracture model calculations, the initiation fracture toughness and unstable fracture toughness of the composites are enhanced by 185.2% and 179.2%, respectively. The increment for fracture energy of the composites reaches up to 1017.1% because of the emergence of blunt and tortuous cracks. The mixed mode Ⅰ-Ⅱ fracture toughness of the composites is increased by 177.1% under four-point shearing load. The initial angle of mixed mode Ⅰ-Ⅱ cracks of the composites decreases with the increase of SSW content. The initiation and propagation of cracks in the composites can be monitored by their change in electrical resistivity. The excellent fracture toughness of the composites is of great significance for the improvement of structure safety in serviceability limit states, and the self-sensing ability of the composites can also provide early warning for the degradation of structure safety.

Effect of Temperatures and Moisture Content on the Fracture Properties of Engineered Cementitious Composites (ECC)

“…To compare and study the deformation capacity in the ECC P-CMOD curve, with varied saturation at the same temperatures, the test specimen closest to the average value of the P-CMOD curve is selected. This data selection method is based on the literature [ 42 ].…”

Smart cement‐sensor composite: The evolution of nanomaterial in developing sensor for structural integrity

“…The appearance of crack and the crack region are localized by observing the drop in voltage using the six‐electrode method without conductive materials 209 . Nevertheless, only the smart cement composites with conductive filler could exhibit excellent self‐sensing property to monitor the crack damage under compression, 46 propagation of multiple cracks, 210 water permeability of the cracked concrete, 211 and provide forewarning of concrete degradation 212 . Among the several parameters, sensitivity and repeatability seem to be the significantly explored sensing properties investigated by the researchers.…”

Electrical Resistivity and Electrical Impedance Measurement in Mortar and Concrete Elements: A Systematic Review

“…Zhang et al [39] used the same configuration but in concrete prisms manufactured with carbon nanotubes and nanocarbon black filler. Ding et al [40] realized stainless steel gauzes to be embedded in cementitious prisms, whereas Dong et al [41] inserted these electrodes in concrete prisms reinforced with super-fine stainless wires.…”

“…Peled et al [75] noticed a dramatic change in impedance values when a sudden growth in crack occurred; the real part of the electrical impedance increases through the fracture process, following the crack opening. Dong et al [41] monitored the cracks initiation and propagation by means of electrical resistivity measurements; in fact, FCR is dominated by the cracks opening, showing the same trend of opening with load.…”