3 research outputs found
Self-healing of concrete cracks by the release of embedded water repellent agents and corrosion inhibitors to reduce the risk for reinforcement corrosion
From the worldwide steel production, approximately 50 per cent is required to replace
corroded steel [1]. In the case of reinforced concrete structures, corrosion of the reinforcement steel
causes crack formation and spalling which leads to serviceability problems. Especially when small
cracks are already present in the cementitious matrix in combination with aggressive ions present
within the environment, a high risk for corrosion exists. Therefore, regular inspection, maintenance
and crack repair are insurmountable for concrete structures. However, costs related to repair works
mount up as not only the direct costs of the repair but also the indirect costs resulting from traffic
jams and possible loss in productivity need to be taken into account. Self-repair of concrete cracks
will have a high economic benefit as the indirect costs as well as a part of the direct costs can be
avoided. In addition, it is assumed that self-repair will lead to more durable concrete structures as
the risk for reinforcement corrosion may be decreased.
The possibility to implement self-healing properties in concrete has been investigated for several
years now. One of the studied self-healing approaches relies on the use of encapsulated healing
agents which are embedded in the matrix. When cracks appear, the capsules break and the healing
agent is released in the crack, causing crack repair. In previous research [2, 3] it was shown that by
using this approach, part of the mechanical properties and the water tightness of cracks was
restored. In this study we investigate whether by encapsulation and embedment of a water repellent
agent (WRA) and/or a corrosion inhibitor (CI), we can reduce the risk for reinforcement corrosion.
A selection of WRA and/or CI were encapsulated and embedded inside reinforced concrete beams
which were cracked to trigger the self-healing mechanism. By electrochemical measurements it was
shown that the risk for reinforcement corrosion was reduced in comparison to untreated cracks
when the cracked beams, containing encapsulated WRA and/or CI, were exposed to a chloride
solution