Title:
Effects Of Post-Fire Curing on Self-Sensing Behavior of Smart Mortars
Author(s):
G. H. Nalon, J. C. L. Ribeiro, L. G. Pedroti, E. N. D. de Araujo, J. M. F. de Carvalho, G. E. S. de Lima, and S. O. Ferreira
Publication:
Materials Journal
Volume:
120
Issue:
1
Appears on pages(s):
181-192
Keywords:
carbon nanomaterials; high temperatures; post-fire curing; selfsensing concrete; smart cement-based composites; structural health monitoring (SHM)
DOI:
10.14359/51738459
Date:
1/1/2023
Abstract:
Post-fire rehydration is an interesting method to recover the structural performance of fire-damaged concrete. This paper evaluated the viability of using cementitious materials containing carbon nanotubes (CNTs) or carbon-black nanoparticles (CBNs) for damage recovery detection and self-monitoring of strain and stress of fire-damaged structures subjected to post-fire curing. Nanomodified mortars were subjected to high temperatures, rehydration, and measurements of capacitive behavior, electrical resistivity, and
self-sensing properties. After 600°C and rehydration, mortars with 9.00% of CBN presented the ability of self-detection of damage recovery, as also verified in mortars with 0.4 to 1.20% of CNT and 6.00% of CBN after 400°C and rehydration. The post-fire curing method filled the pores and microcracks of the cementitious matrix with nonconductive rehydration products, increasing their electrical resistivity. Mortars with 0.80 and 1.20% of CNT presented self-monitoring of strain and stress after 400°C and rehydration, as also observed in mortars with 9.00% of CBN after 600°C and rehydration. The post-fire curing process also increased the selfsensing properties because nonconductive rehydration products obstructed conductive stretches, improving tunneling conduction mechanisms rather than contacting conduction. These self-sensing materials are promising alternatives to evaluate post-fire curing processes and self-monitor the strain and stresses of next-generation
smart structures.