Strength criterion of recycled aggregate concrete under triaxial Compression: Model calibration

Utilization of recycled aggregate concrete (RAC) can promote the development of green building materials since it can make full use of waste concrete. The mechanical properties and failure criterion of RAC under triaxial compression is the computational basis for design of RAC structural members. However, an explicit and unified approach for assessing the failure surface of RAC under both traditional triaxial compression and true triaxial compression condition is extremely limited. Aiming to provide a solution to figure out the above-mentioned technical bottleneck, firstly this study evaluated the applicability of existing failure criterion developed based on natural aggregate concrete using an experimental database including 123 cylindrical RAC specimens; and then an equation of compressive meridian (i.e., Lode angel is 60°) in octahedral stress space was proposed with the help of this database. Further, the formula for tensile meridian of RAC (i.e., Lode angel is 0°) was established based on 24 cubic RAC specimens collected from available literature. The influence of high temperature was also considered in both compressive meridian and tensile meridian formula. A complete failure surface of arbitrary stress condition (i.e., the Lode angle ranges from 0° to 60°) was determined. Finally, the proposed equations for failure surface of RAC in the cases of room temperature and high temperatures were validated with reference to experimental results.