13th International Conference on Fracture June 16–21, 2013, Beijing, China -5- Figure 2. Variation of J-integral at maximum load with the notch root radius for the plain and reinforced mortars The impact energy results are presented in Table 5, for the three mortars conditions. The individual energy levels shown in the table correspond to the average of five tests with a standard deviation of about 12%. Table 5. Impact energy of the plain and reinforced mortars Mortar Impact Energy (J) plain 0.45 ± 0.05 reinforced with 25 mm fibers 2.04 ± 0.22 reinforced with 45 mm fibers 3.28 ± 0.35 One can therefore conclude that the use of sisal fibers as a reinforcing element in mortar results in a considerable increase in the impact resistance and that such an increase is considerably more significant for the longer fibers. This beneficial influence is attributed to the fact that, even as the matrix cracks, the load carrying capacity is replenished by invoking fiber loading. This maintains the specimens’ integrity as they continue to deform and hence to absorb more energy. The superiority of long fibers in promoting impact resistance is related to the higher load carrying capacity, as well as deformability, of the mortars reinforced with such fibers. The correlation between the impact energy levels and J-integral results is presented in Fig. 3, whereby an essentially linear relationship is seen to exist between the two parameters.
RkJQdWJsaXNoZXIy MjM0NDE=