The bond between fresh and hardened concrete can be subjected to various stress states depending on the application and service conditions. Four test methods, reflecting different stress states at the bond between the fresh and hardened concrete, are evaluated. The four methods are a slant shear test, an indirect tension test and two different flexure tests. The slant shear test is shown to be consistent and the most sensitive test in showing the strength of the bond, and was used to evaluate the effect of the following parameters on that strength: (1)the water cement ratio of a portland cement mortar;(2)the thickness of the bond layer;(3)the effect of various curing conditions;(4)the effect of wetting the surface of the hardened concrete before application of the portland cement mortar bonding agent; and(5)the effect of delay between mixing a copolymer Polyvinyl acetate (PVA) bonding agent, and its application to hardened concrete.We conclude that copolymer PVA is a poor bonding agent over a wide range of curing conditions and that the thickness of a portland cement mortar layer has a strong influence on bond strength. The other factors did not affect strength significantly.
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- Testing of Bond Between Fresh and Hardened Concrete
J. S. Wall
N. G. Shrive
B. R. Gamble
- Springer US
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