Using concrete pavement on OSD as a countermeasure for fatigue has been tried
not only in Japan. Moergijk bridge in Netherlands was resurfaced using 50mm thickness
of high performance reinforced concrete4). In Japan, Nagoya Expressway Public
Corporation (NEPC) had used SFRC pavement in 1980’s for several ramp bridges, though,
the application was not for fatigue but for stabilizing pavement on ramp bridges with
slope5). And another difference is that NEPC’s SFRC is connected to deck plate only by
studs as shown in Figure 4. As a countermeasure for fatigue, Japan’s first application was
on Yokohama Bay Bridge (YBB)’s lower deck in 2004. The upper deck had already been
opened to traffic since 1989. Since the lower deck was additionally constructed, the SFRC
pavement was not repair/ reinforcement of existing structure. Early strength cement was
used for SFRC whose thickness was 75 mm6). Adhesive was used all over the deck plate to
connect SFRC. Studs were set, avoiding wheel load paths, only at the center of the lane and
the edges of SFRC in transverse direction. And in longitudinal direction, they are put in
two lines manner with 300mm spacing each other. After the completion of the SFRC
pavement, cracks on SFRC were found as shown in Photo 1. Major cracks are longitudinal
and its maximum width is 0.3mm7). The cracks had been filled with acrylic. Thanks to the
upper deck, rainfall does not seem to affect so much and in fact, no deterioration has been
observed in terms of performance as pavement yet. However, this incident has brought a
major concern about durability of SFRC Pavement.