Yukinori SUZUKI

Flexural crack width of RC beam with short fiber and fiber mesh reinforcement

SupervisorFTakumi Shimomura

This study investigates the flexural loading test of RC beams with short fiber and fiber mesh reinforcement.
In this study, 2 types of aramid fiber, steel fiber and aramid fiber mesh are used.
Average member strain beam, average concrete strain and crack width at the bottom face of the beams were measured in the tests. Moreover, the average crack space was calculated from the number of cracks.
In the same loading condition, the average crack width in fiber reinforced concrete (FRC) beams is smaller than that of normal RC beams. It means when the fiber is mixed into concrete, the average crack width becomes smaller.
When a large amount of fibers was mixed, the effect of crack width reduction did not increase. The aramid fiber mesh showed the same effect of crack width reduction as the short fibers.
For all FRC beams when the load increased, the average crack space decreased. The improvement of crack detachability decreased the average crack space and there is a relationship between the improvement of crack detachability and the effect that crack width decreases.
The average crack width was compared with the value calculated from deformational compatibility condition. It appears that the improvement of crack detachability is the main factors for decreasing crack width.
When the fiber is mixed into concrete, the tensile stiffness of concrete slightly decreased. Simultaneously, crack detachability improved and crack interval became smaller. The improvement of crack detachability exceeded the decrease of tensile stiffness. As a result, crack width became smaller.