Cracks are ubiquitous in concrete and reinforced concrete structures and are generally caused by the material volume instability (e.g., shrinkage), mechanical or environmental loading.
Regardless of the cause of the cracking, cracks reduce the service life of concrete structures because they allow water and other aggressive agents to ingress into concrete at a higher rate. While design to control cracking may be possible for new structures, the effects of cracks on the existing concrete structures need to be somehow mitigated.
To mitigate the effects of cracks, they are commonly sealed using a sealant. Different types of sealants are commercially available and their effectiveness depends on their ability to penetrate into the cracks and withstand the mechanical loads and weathering. In general, low viscosity sealants (e.g., silane) are more effective in penetrating into cracks with a small crack width and high viscosity sealants such as epoxy resin based sealants are more effective in sealing cracks with a larger width. In selecting sealants, the orientation of the surface that contains cracks is also important. Low viscosity sealants are generally more effective for sealing cracks on horizontal surfaces, while high viscosity sealants can be easily applied to vertical and overhead cracks (often using an injection method).
A variety of sealants with different chemistry are commercially available; however, their relative performance against each other is largely unknown since field experience with some of them is limited. In addition, with the recent supply chain interruptions, there is a need for alternative sealants that can deliver satisfactory performance to avoid increased cost and delay of projects. The goal of the present proposal is to address
these challenges.
