Issue34

A. Satoh et alii, Frattura ed Integrità Strutturale, 34 (2015) 397-405; DOI: 10.3221/IGF-ESIS.34.44 402 0 2 4 6 8 0 0.01 0.02 0.03 0.04 0.05 σt (MPa) ε TSD1 0 2 4 6 8 0 0.01 0.02 0.03 0.04 0.05 σt (MPa) ε TSD2 0 2 4 6 8 0 0.01 0.02 0.03 0.04 0.05 σt (MPa) ε TSD3 Substrate concrete Repair material Wall Effect Interface (a) High strength interface. (b) Middle strength interface. (c) Low strength interface. Figure 8 : TSDs for matrix element used for FEM analysis. But in the case of TSD2, the responses of Model S and Model W are very different. It means that Model S has a brittle behavior reflecting the straight crack path along the interface shown in Fig. 10(a2) and (b2), whereas the crack paths for Model W-N and W-A (Fig. 10 (c2) and (d2)) are the same as depicted in Fig. 10(c1) and (d1). In the case of TSD3, the crack paths for Model W-N and W-A extends along the crooked interface as shown in Fig. 10(c3) and (d3). Then the response is determined by the brittle behavior of interface. Reflecting the total length of crack path of Model W, which is 1.379 times of Model S, strength of Model W is about 1.15 (1.13 for W-N and 1.16 for W\A) times of Model S. In all the cases which include aggregates (S-A and W-A), some cracks appear along the aggregates located far from the center. But the response is not so different from that of the blank cases. The reason for that may be the orderly location of the aggregates. 0 1 2 3 4 5 6 0 0.0025 0.005 0.0075 0.01 Stress (N/mm 2 ) Deformation (mm) 0 1 2 3 4 5 6 0 0.0025 0.005 0.0075 0.01 Stress (N/mm 2 ) Deformation (mm) 0 1 2 3 4 5 6 0 0.0025 0.005 0.0075 0.01 Stress (N/mm 2 ) Deformation (mm) S-N-TSD3 S-A-TSD3 W-N-TSD3 W-A-TSD3 (a) Response for TSD1. (b) Response for TSD2. (c) Response for TSD3. Figure 9 : Analyzed stress-deformation response for models with interface layers. E NHANCEMENT OF MECHANICAL PROPERTIES For repair material ig. 11 represents the relationship between mechanical properties or between some features and Ft of monolithic repair. In Fig. 11(a), it is shown that the effect of void (inclusion of 28.6%) is more detrimental to GF in the case of ductile matrix which decreases 44% than in the case of brittle matrix which decreases 36%. In Fig. 11(b), it is shown that high modulus aggregates have a positive effect to strength in the analyzed case of brittle matrix as mentioned before. Also this agree with the experimental results depicted in Fig. 12. Ft is also dependent to RL, which is shown in Fig. 11(c). This is the same results as discussed in a reference [8]. Though the effect of RL to repair is eminent, the effect to the repaired mortar with interface is not so clear because of the many material properties involved in the crack path. F