Piezoresistive monitoring of FRP –concrete interfacial behavior using carbon nanotube yarns

Abstract This study develops an innovative carbon nanotube yarn (CNY)‐based sensing method for real‐time interfacial behavior monitoring in carbon‐fiber reinforced polymers (CFRP) strengthened concrete systems. Single shear testing and piezoresistive monitoring were carried out on CFRP–concrete composite specimens to analyze the interfacial bond behavior and piezoresistive response of CNY mounted on CFRP. The results demonstrate the ability of CNY to monitor the interfacial loading behavior. Through bond slip relationship characterization, bilinear constitutive bond parameters are extracted and their quantitative influence on CNY monitoring signals is revealed. Either increasing local bond strength or reducing the corresponding slip leads to a more gradual rise in the piezoresistive response curve, while the ultimate slip shows minimal influence except for extending the curve to higher applied forces. The piezoresistive response accurately captures the effects of varying bond parameters, demonstrating piezoresistive monitoring is an effective method for interfacial performance characterization.