No abstract

Concrete and cement permeability (due to cracking and porosity) and brittleness can be addressed by the incorporation of chemicals in fibers, which are later released. This changes the material matrix properties just in time to prevent and repair damage. The conventional method to reduce cracking is fiber reinforcing and permeability is reduced by sealants and waterproofers or creation of a tighter microstructure of fewer, smaller pores. Our research combines the fibers and sealants together for internal timed release of chemicals from hollow fibers.This research specifically concerns the repair or healing of cracks and filling of voids in cementitious matrices by the internal release of repair chemicals from inside fibers into the hardened matrix. Two active and one passive mode of activation are studied.

No abstract

The goal of this research project is to expand the previous work on a timed adhesive release system for the repair of cracks in concrete. The performance criteria for the adhesive are that it must have a long shell life, be resistant to extreme temperatures, have a high viscosity so it can flow easily into cracks in concrete and it must be strong enough to repair the cracks. The method of encapsulating the adhesive must not degrade over time and it must not be costly. A three-part methylmethacrylate adhesive system was chosen. The adhesive was released from hollow glass tubes coated with a brittle breakable sealer. The experimental results showed the release of the three-part methylmethacrylate adhesive into the matrix created a bond that restored the lost strength due to the cracking and increased flexibility.

No abstract