Yuguo ZHAO

Effectiveness of Upgrading of Bending Toughness of Concrete by Mixing Aramid Short Fiber

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Supervisor:Takumi SHIMOMURA

In recent years, the exfoliation of concrete block from tunnel and high bridge has occurred. The durability of concrete structures has become a problem. The method of improving the bending toughness of the concrete by mixing with fiber is mostly used as the measure to prevent exfoliation. But, as the technical standards and rational design techniques have not yet been established, it is difficult to choose the most proper materials from various kinds of fibers.
The purpose of this research is to examine the bending toughness of Aramid Fiber Reinforced Concrete, comparing with Vinyion and Steel Fiber Reinforced Concrete. In order to solve the problems of the past evaluation measures on bending toughness, the area around the stress-strain curve is devided into two parts which are the part depending on the the characteristics of plain concrete and the part depending on fibers, and a method is put forward by only evaluating the latter one. This evaluation method can avoid the influences of sudden stress declining. In case the ratio of mixing fiber gets low, more exactly evaluation on the effection of fiber reinforcement can be obtained.