混凝土结合界面, 黏结力, 密合剂, 结石体, 超缓凝

Concrete bonding interface, which is easy to crack, has always been a weak part and become a worldwide technical problem. Through further study of the interface bonding mechanism, the "dual interface- multilayer zone" interface structural model and the "two- factor stress balance" interface close-fit mechanics model are innovatively introduced. And by combination of "stress- enhancement" and "stress-elimination", a new environmental friendly interface bonding material——new and old concrete interface bonding adhesive is developed. The cement-based cementitious material is used as the matrix. Various active powder materials are introduced to optimize the hydration reaction process, to improve the crystal structure and size of interfacial stone body, and to generate a denser and stronger mineral. And volume-swelling component and water-retaining component are added to reduce the volume shrinkage and dehydration shrinkage during the hardening process of adhesive, which ensures the volume stability during the hardening process. An appropriate amount of super retarding component is introduced to extend the setting time, which can use its plasticity to absorb most of the autogenous volume deformation and shrinkage deformation of the new concrete. Water-retaining materials and surfactants are added to improve the workability of bonding layer and the construction performance. These measures make the interface bonding layer have similar physical and mechanical properties with the old and new concrete, which not only improves the bonding strength of interface, but also effectively reduces the harmful interface constrainting stress, thereby making this combination stronger and more durable. The practical application to Danjiangkou dam heightening and other projects has proved that the concrete interface treated with the new and old concrete interface bonding adhesives has excellent bonding performance and significant adhesion effect.

concrete bonding interface, bonding strength, bonding adhesive, stone body, super retarding