Interface Bond Characterization of High-Performance Concrete Overlays and Substrate

摘要

Overlay systems have been used by many states for the protection of bridge decks, but the premature delaminations and failures have been observed in many cases. A comprehensive study was recently defined to investigate overlay performance in collaboration with the West Virginia Department of Transportation-Division of Highways (WVDOH). As part of a comprehensive program, the present study is concerned with the properties of four types of overlay mixtures and the interface bond strengths between the overlays and substrate concrete. All the materials used are of interests to WVDOH. Four overlay types were: silica fume modified concrete, latex modified concrete, fiber reinforced concrete and slag modified concrete. With these overlays, statistical design of experiments were conducted for the evaluation of the influences on bond strength of four factors: aggregate types, surface preparations, use of bonding slurry, and substrate age using a recently developed direct shear test apparatus. Results show that except for bonding slurry, all the parameters had strong influence on shear bond strength. The results of this study will serve the purpose of screening and selection of overlays from a large number of variables, and will finally help to develop guidelines by WVDOH for future implementations of concrete overlays in the field.