ABSTRACT
A restraint ring test is used to assess the cracking potential for early-age cementitious materials and the residual stresses of the restraint mortar ring are numerical analyzed by considering the comprehensive effects of hydration heat, autogenous and drying shrinkage, creeping and restraint. In the present simulating method, the stress field of the restraint ring is treated as the superposition of stress fields caused by hydration heat, external restraint, autogenous and dry shrinkage and creep of early-age concrete. The factors including the properties of materials, environmental parameters such as relative humidity and temperature, geometry effect of the specimen, change of the steel ring due to temperature variation of hydration of the mortar ring, and the relative constraint effects of steel ring to mortar ring are taken into account. The temperature in the ring due to hydration is recorded and the elastic modulus, the creep strain, and the split tensile strength are measured to validate the model. The age of cracking is predicted by comparing the estimated maximum tensile stress in the restraint mortar ring and the measured split tensile strength of materials. A sound agreement of the simulated results comparing with the restraint ring-test is observed.
