Electromechanical response of smart ultra-high-performance concrete beams under flexure: Effects of filler type and electrode spacing

Abstract

This study assessed the electrical resistance of smart ultra-high-performance concrete types (S–UHPCs) in the compressive and tensile zones of the flexural specimens subjected to four-point bending tests. The investigated S–UHPCs included a normal ultra-high-performance concrete (UHPC) (M1) integrated with fine steel slag aggregates (FSSAs) (M2) and a UHPC composed of multiwall carbon nanotubes and FSSAs (M3). The electrical resistance of these S–UHPCs remained relatively stable up to the limit of proportionality followed by a significant decrease. The suitable interelectrode distances for electrical resistance change measurements of the S-UHPC beam (100 × 100 × 400 mm3) were found to be 30:50:30 mm. Moreover, M2 demonstrated the highest stress sensitivity coefficient in the deflection hardening region (SSCMOR) at both tensile and compressive zones, with values of −4.29 and −1.20 %/MPa, respectively. The SSCMOR for M2 in the flexural–tensile zone was 3.58 times greater than that in the flexural–compressive zone.