The Structural and Durability Properties of Various Concrete Repairs

摘要

Many old concrete structures exist and are in need of repair. The structural deterioration will accelerate with advancing age and progressively diminish their service lives. Methods of evaluation and repair are necessary. Durable concrete can be produced and placed; therefore, the main problem is to have a durable interface between the old and the new concrete. The bonding of epoxy resin, cement mortar, latex polymer mortar, and latex polymer mortar plus fiberglass fabric was tested in a freezing and thawing environment subjected to conditions of compelte submergence, one-half submergence, and stress conditions. Many surfaces are subjected to abrasion. The latex polymer was tested to determine if it helped to increase abrasion resistance. These tests showed that for early ages of repair water will collect at the interface of the old and new concrete and when the water concentration is sufficient and freezing occurs, the overlay will be debonded. The epoxy bond exhibited a constant number of specimen failures with cycles of freezing and thawing. The concrete-to-concrete bonding had more specimens fail at early intervals of freezing and thawing than in later intervals. All four bonding types had about the same final percent failures in the freezing and thawing environment, which in all probability suggests that the failures due to water collecting at the interface for early ages of repair are essentially comparable. Specimens which were subjected to freezing and thawing plus stress showed more failures than the unstressed specimens.