Empirical calculation method of residual flexural tensile strength fR,1 of SFRC
An empirical calculation method is proposed in the article for the calculation of residual flexural tensile strength of steel fibre reinforced concrete. The method was developed analyzing factors which have an influence on residual tensile strength, and using the experimental results of 446 specimens. Assuming that the residual flexural tensile strength depends on three functions the relevant variables and constants were deduced, and so the optional functions were established. The proposed calculation method is suitable for the SFRC, where fibre content varies from 15 to 80 kg/m3 as well as mean compressive strength varies from 25 to 60 MPa. Only circular cross-section hooked end steel fibre is available however, traditionally vibrated as well as self-compacting concrete is suitable for this method. The residual flexural tensile strength (fR,1) is used in various crack width calculation methods, and it should be determined experimentally according to standards. Therefore, the proposed calculation method has a great practical benefit.