Feasibility Study of Reactive Powder Concrete Applied in Superstructure of Bridges

The reactive powder concrete (RPC) was first published by French in 1994 and it had been widely applied in bridge engineering in advance countries such as Europe and Japan due to its great properties. In Taiwan, the climate is hot and humid and it would deteriorate the old structure rapidly. On the other hand, Taiwan is highly developed area and lack of land resource. If we applied RPC in superstructure of bridges, both the member section and the self weight would be reduced. Simultaneously, the low permeability can inhibit the chloride attack and prolong the service life of the bridge. 　 This study is divided into two parts. The fisrt part will find out the mechanical properties and durability properties of RPC. The conclusion of mechanical properties of RPC is that under high temperature(90℃) curing, the strength can reach the optimal value at age of 7 days. On the other hand, under room temperature curing, the compressive strength will increase with the increasing curing period and will reach the same strength as that under high temperature curing. The development of strength will slowed down after the age of 56 days and the performance between high temperature and room temperature will reach the same level at age of 90 days. In addition, the conclusion of durability properties of RPC is that the performances in both stability of volume and the compactness of internal structure are better compared with the performaces of OPC. It is contributed to the accelerated hydration and pozzolanic of RPC under high temperature curing, which reduce the water loss and form a dense internal structure in a short period. At the same time, adding steel fiber can also increase the internal bonding strength to keep its volume stable. 　　Secondly, the material parameters of RPC obtained in the first part are used to design a superstructure of bridge and check whether the superstructure passes the recommendation adopted in Taiwan. According to the recommendation adopted in Taiwan, the loading, the prestressed losses and ultimate capacity are calculated, and it is showed that the prestreesed loss of RPC superstructure is of better performance than the one with OPC. Also, applying RPC can reduce the size of section and self weight. Finally, the original mix proportion is adjusted and the possibility of the precast segmental method is also evaluated. Moreover, a real size specimen is casted and tested in this study. The accuracy of the analysis of the design is reserved.