Extensive research has already been performed on self-healing concrete based on a
triggered release of liquid polymer precursors from a carrier, especially during the
past decade. However, tests on large concrete specimens are still seldom performed
and the self-healing techniques used are often not practical or effective if
implemented at a large scale.
This paper presents an analysis of the most relevant properties for carriers that are
critical for moving the technology closer to a realistic implementation. The study
contemplates the assessment of the dimensions of tubular glass capsules that result
in a high survival rate if directly added to concrete during mixing, while still being able
to rupture during realistic crack formation in the host concrete matrix.
Finally, a trial implementation of randomly dispersed glass tubular carriers in concrete
beams is presented. This system is composed of a typical OPC concrete with tubular
glass capsules added during the mixing process. It is shown that this system works
and the crack planes cross several capsules that subsequently release the polymer
precursor into the crack. However, the dosage used needs to be increased if a
satisfying healed area is to be achieved
