Adapting of the willam-warnke failure criteria for young concrete

The proposition of two failure criteria for young concrete is presented in the paper. The proposed failure criteria refer to well-known Willam-Warnke [1] 3- and 5-parameter model. Slight mo-difications of these models, aiming to fit the experimental evidence better and to remove some shortcomings of the original Willam-Warnke [1] models were introduced recently by Majewski [2, 3]. These suggestions connected mainly with introducing caps in the area of tensile and low compressive mean stress were adapted for young concrete. Additionally, the results of the original triaxial compression tests of young concrete supported the concept of the proposed models and enable the determination of the expression describing the failure surface. The triaxial tests were done on cylindrical specimens using ELE Hoek Cell TNX. The age of testing concrete was 1, 3, 7 and 28 days in each series.