Ultrasonic wave transmission to monitor the performance of self-healing concrete based on encapsulated polymer precursors

 

J. Feiteira1,E. Gruyaert1, N. De Belie1

 

1 Magnel Laboratory for Concrete Research, Ghent University, Technologiepark-Zwijnaarde 904, 9052 Ghent, Belgium – e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

ABSTRACT

Self-healing concrete aims at the autonomous healing of small cracks, with widths in the order of a few hundred micrometers. This way, the service life of reinforced concrete structures can be extended and their watertightness guaranteed for longer periods, while costly and potentially complex repair works can be avoided.

As with other emerging concrete technologies, this novel repair technique poses new challenges regarding the conception of new test methods that are able to assess its performance in realistic conditions and able to continuously monitor it. Thus, this paper presents results of applying the transmission of ultrasonic shear waves for continuous monitoring of small scale cement mortar specimens cracked and healed with encapsulated precursors of flexible polymers.

Preliminary results on larger concrete specimens showed already that this technique successfully detects the continuous hardening of the precursors after rupture of the capsules and further filling of the crack, corresponding to an increase of the amplitude of shear waves transmitted through the healed crack. Additionally, the reverse was observed when failure occurred, due to rupture of the polymer’s matrix or to its detachment from the crack walls.

In this study, the transmission of ultrasonic shear waves is used to assess the limits of the elongation of the polymers bridging the cracks and their resistance to fatigue while healing a moving crack induced by cyclic loads. The polymer precursors used include moisture curing polyurethanes forming solid films or foams with closed-cell structure.

 

 

 ACKNOWLEDGEMENTS

The research has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 309451 (HEALCON).

 
This project has received funding from the European Union’s Seventh Framework Programme
for research, technological development and demonstration under grant agreement no 309451.
Saturday the 21st. © 2013 Universiteit Gent.