نوع مقاله : مقاله پژوهشی
موضوعات
عنوان مقاله English
نویسندگان English
A correct understanding of the failure mechanism of self-compacting concrete (SCC) plays an important role in the design of SCC structures and a better understanding of the behavior of structures made of it. Adding steel fibers in self-compacting concrete and different ratios of water to cement can change the cracking behavior and its failure parameters. Therefore, in this research, using 120 grooved beams under three-point bending test, the effect of water-cement ratio (w/c) on the fracture properties and ductility of fiber self-compacting concrete was investigated. The fracture parameters obtained in this study are total fracture energy ( ) and characteristic length ( ) from fracture work method (WFM) and initial fracture energy ( ), effective length of processing area ( ), brittleness number and fracture toughness from size effect method (SEM). The results showed that , with increasing w/c ratio from 0.35 to 0.7 decreased by 23% and 24% respectively. Also, with the increase of w/c ratio from 0.35 to 0.7, the value of parameter and increased by 22 and 47%, respectively, while the brittleness number ( ) in SEM decreased by 14.5%. By decreasing the w/c ratio, the strength of the surface transition zone and cement paste increased and the ductility decreased. The ratio of fracture energy obtained from WFM ( ) to initial fracture energy obtained from SEM ( ) for different w/c ratios was equal to 9.9 with a coefficient of variation of 4%. Finally, the obtained values for mechanical properties and test variables were used to develop multivariate prediction models for failure parameters of self-compacting concrete containing fibers with different w/c ratios, which have acceptable accuracy when compared with the results of other researchers.
کلیدواژهها English