Chloride ion penetration resistance of self-sealing concrete by in-situ generated hydrogels

Abstract

The formation of cracks in concrete of any form is highly inevitable and this problem diminishes its durability. In worst cases, such cracks can weaken the members of a structure and potentially resulting in total failure since its structural integrity has been compromised. This is especially so for concrete with exposure to corrosion. Substances such as chlorides are one of the many reasons for such corrosion as they can penetrate through these cracks and create a problem of steel reinforcement corrosion as well as the degeneration of concrete. As a result, in certain cases, when cracks have been identified, corrosion might have already taken effect. For underlying cracks that are more difficult to identify, such issues may raise a much larger concern. This have allowed researchers to investigate the possibility of integrating self-sealing properties into concrete materials so as to allow for the reactive healing to take place as soon as cracks starts appearing. The study of seal-sealing of concrete has grown in recent times as a very probable way towards increasing its sustainability. One of the methods in relation to this study is via in-situ generated hydrogels. In this project, the focus is on the resistance to chloride ion penetration of self-sealing concrete through this method. Concrete samples with different mixture contents were prepared to produce different selfsealing levels as part of this study. This is to examine how those self-sealing concretes would perform under chloride related corrosive conditions and how much it would be able to resist the penetration as compared to a typical sample. Such properties of the concrete samples were tested after 28 days of curing and an additional self-sealing period for the respective specimens. It can be concluded that this method of self-healing does help to strengthen resistance to chloride ion ingress to some extent through the various methods and evaluations done later in the project. However, it is not certain to what amounts can the healing mechanism can prevent, lessen, or slow down the problem of concrete reinforcement corrosion as there are also many of factors and parameters to consider. Further studies and research have to be conducted to derive the ideal conditions and specifications for total protection against chloride penetration of the reinforcement materials.