Self-sensing Properties of Concrete with Electric Arc Furnace Slag and Steel Fiber

Abstract

In this study, 20 wt.% electric arc furnace slag (EAS) and 0.75 vol.% hooked steel fiber (SF) were used to improve the electrical conductivity and investigate the self-sensing properties of concrete. In addition, electrical and material properties were evaluated. Test results showed that the setting time was delayed and strength properties were diminished compared with those of plain ordinary Portland cement (OPC) specimens when using EAS. However, the compressive strength was similar to that of OPC, and ductility was increased by adding SF. The electrical resistivity of concrete was considerably reduced when incorporating SF and EAS. In addition, the combined use of EAS and SF resulted in good self-sensing performance in terms of the fractional change in resistivity (FCR). Moreover, the FCR was slightly decreased when using EAS or SF. Finally, the linear relationships between the FCR and compressive strain were observed, and the EAS-SF combination resulted in the highest gauge factor at approximately 97.2 when compared to other specimens.

Effects of Steelmaking Slag and Moisture on Electrical Properties of Concrete

“…According to the method specified in ASTM International, setting test specimen was ∅150 mm × 150 mm in size, and the compressive and splitting tensile strength test specimens were fabricated into cylinders of ∅100 mm × 200 mm [21][22][23][24]. Concrete test specimens for assessing electrical characteristics were 150 mm cubes considering the maximum dimensions of the coarse aggregate, as shown in Figure 2 [4,12]. Copper plates which had dimension of 20 mm × 150 mm were used as electrodes, and four copper plates were embedded in the concrete at intervals of 20 mm.…”

“…Environmental and structural stressors shorten the life of concrete. Therefore, there is an increasing interest in the development of efficient, economic, and accurate methods to assess the structural health of concrete structures [1,4]. Conventional and commercial strain sensors for infrastructure can only assess the local behavior of structures, and they are limited in use due to poor durability, low sensitivity, and low gauge factors [1,[4][5][6][7].…”

“…Therefore, there is an increasing interest in the development of efficient, economic, and accurate methods to assess the structural health of concrete structures [1,4]. Conventional and commercial strain sensors for infrastructure can only assess the local behavior of structures, and they are limited in use due to poor durability, low sensitivity, and low gauge factors [1,[4][5][6][7]. To address the need for accurate and practical concrete monitoring methods, researchers have proposed "smart concrete structures" that measure load/deformation and stress/strain by incorporating conductive materials [2][3][4].…”

“…It is well-known that incorporation or replacement ratio of conductive materials, distribution states of fillers, and types of additives strongly influence the conductivity of cement composites and concretes. Choi et al [4] found that the incorporation of 0.75% steel fibers into concrete resulted in an effective conductive path while entangling each other in the concrete matrix. Lee et al [8] assessed the effect of carbon fibers on the electrical properties of cement composites and found that incorporating ratios of carbon fibers that exceeded 1% increased the porosity of the cement composites.…”

Influence of CNT Incorporation on the Carbonation of Conductive Cement Mortar

“…Choi E.K. et al [13] used steel fibers both to embed the self-sensing system into the concrete structures and to strengthen the tensile strength. In addition to the incorporation of steel fiber in concrete mixtures, using carbon nanotubes (CNTs) has Materials 2021, 14, 6721 2 of 14 been investigated by many researchers and scholars because CNTs can give the concrete composites the conductivity [14][15][16].…”