Engineering

Materials science

Optical time-domain reflectometer

Visualization

Bending

Optical fiber

Telecommunications

Computer science

Fiber optic sensor

Fiber optic splitter

Mechanical engineering

Artificial intelligence

Composite material

Fiber

Time domain

Structural engineering

Distributed acoustic sensing

Reflectometry

Computer vision

Automation in Construction

This paper presents a method to measure and visualize strains and cracks in high-performance fiber-reinforced concrete using distributed fiber optic sensors based on optical frequency domain reflectometry. Two beams were prepared using high-performance concrete with two types of fibers and post-tensioned with carbon-fiber-reinforced polymer (CFRP) tendons. The beams were instrumented with distributed sensors which were installed using two methods compatible with realistic construction. The beams were tested under four-point bending until failure. The distributed sensors measured strain distributions over the length of the beams in real time. The strain distributions are analyzed to detect, locate, trace, quantify, and visualize cracks during the processes of their initiation and propagation. The crack widths measured from the distributed sensors as well as a crack microscope are in a good agreement. This study is expected to promote distributed sensing technology for monitoring and control of construction and operation automation in new and existing structures.

Measurement and visualization of strains and cracks in CFRP post-tensioned fiber reinforced concrete beams using distributed fiber optic sensors