The Old Concrete Bonding Surface Penetration Test

The thesis is a part of subject "Research on mechanism of adherence and measure method of young on old concrete", which is sub-subject of national momentous foundational research subject (Climbing Project B) <> , and national nature science found(59778045) < .Impermeability usually are used as a key index to measure the durability of concrete, which are also as an important basis to evaluate the durability of new-old concrete adherence. Especially for those repaired hydraulic concrete structure, the adherence of new-old concrete may produce seepage under water pressure. The author had conducted experimental research on the impermeability of the interfacial bond of new-old concrete under water pressure, and hoped that the research could be used to evaluate the safety and durability of bond performance after having been repaired and retrofitted.According to impervious testing machine, the composite impervious specimen was designed and 168 specimens were presented. The influences of several factors on bond seepage properties were discussed, such as interfacial treatment, interface adhesive agent and the surface of old concrete with notch groove. Also the seepage properties and mechanical parameter, such as equivalent hydraulic fracture width, permeability coefficient and seepage law, were explored.The test results indicated that the interfacial permeability of new-old concrete was greater than that of new or old concrete itself, and the bonding interface was main path of seepage. The calculating formulas of permeability coefficient and equivalent width of hydraulic fracture were conducted. The equivalent hydraulic fracture width was from 0.11 m to 0.27 m , 1.2 10-8~4.8 10-9 cm/s for permeability coefficient, the highest was 1.8 10-4~2.5 10-4cm/s.