Takahiro Yanai

Fundamental Study on the Construction of Bridge Surface Waterproof Intermediate Layer Using Cutting Asphalt Remaining Layer

Osamu TAKAHASHI, Takeshi NAKAMURA

On the boundary between the bridge surface pavement and the concrete floor slab of the road bridge, a floor surface waterproof layer is provided to prevent deterioration of the concrete floor slab.The service life of this floor plate waterproof layer and the asphalt pavement layer are from 15 to 30 years and from 5 to 15 years, respectively. Consequently, there is a difference in the useful life between the floor plate waterproof layer and the asphalt pavement layer. Therefore, at the time of changing the bridge surface pavement, even if the floor surface waterproof layer is less than the useful life, it will be reinstalled.
Also, when replacing the bridge pavement, a massive machine will be used to strip the asphalt pavement layer, which will cause some damage to the surface of the concrete floor slab.
When the concrete floor slab is damaged, restoration work is carried out. As a result, it is impossible to restore it in limited construction cost and construction period completely.
From the above, if the asphalt pavement layer remaining after cutting could be reinforced and reused as an intermediate layer, it will not damage the concrete floor slab and the floor surface waterproof layer.
In this study, the present study investigated constructing a bridge surface waterproof intermediate layer by spreading the emulsion to the remaining asphalt pavement layer after cutting to reinforce it.Therefore, the present study evaluated the performance of the waterproof intermediate layer reinforced with emulsion. In addition, this study examed the feasibility of the bridge surface waterproof intermediate layer.The experiment results showed that there was no waterproof and adhesion problem when the spraying amount of the emulsion was 1.2 ?/ m 2 and the crack width was 1.0 mm or less.Furthermore, it was found that the useful life of the asphalt pavement layer could be extended by spraying the emulsion.