Issue 35

L. Chunjiang et alii, Frattura ed Integrità Strutturale, 35 (2016) 500-508; DOI: 10.3221/IGF-ESIS.35.56 502 Categories Serial number Quantity Size of specimen (1×h×t/mm) Crack- depth ratio Depth of cracks [mm] Thickness of cracks [mm] RCC RCC1504 12 150×150×150 0.4 60 3 RCC1504 6 150×150×150 0.5 75 3 RCC1504 6 150×150×150 0.6 90 3 RCC1504 6 300×300×150 0.4 120 3 RCC1504 6 400×400×150 0.4 160 3 RCC1504 6 500×500×150 0.4 200 3 Common concrete PC1504 9 150×150×150 0.4 60 3 PC1504 6 150×150×150 0.5 75 3 PC1504 6 150×150×150 0.6 90 3 PC1504 9 300×300×150 0.4 120 3 PC1504 9 400×400×150 0.4 160 3 PC1504 9 500×500×150 0.4 200 3 Table 2 : Working conditions of specimen. Testing Devices Testing devices are shown in Fig. 2. Clip-on extensometer Wedge holder Load sensor Top board Signal amplifier Data acquisit ion system Computer Figure 2 : Acquisition of test data with wedge splitting method Test Results Specimen over 150×150×150 mm 3 is calculated with following formula, and specimen (150×l50×l50 mm 3 ) uses regular computing method [9-11]. Unilateral opening specimen is affected by axial tension, and stress intensity factor (SIF) can be calculated with formula below:   1 / L K af a D    (1) where,   / h P D t    and           2 3 4 / 1.122 0.231 / 10.55 / 21.71 / 30.382 / f a D a D a D a D a D     