Study On The Effect Of Curing Temperature On Tensile Creep Of High Performance Concrete At Early Ages

It is very important to grasp tensile creep behavior of hige performance concrete (HPC) at early ages, when stress analysis and crack prediction due to volume change exists. In this paper, the effects of initial loading ages and curing temperatures on tensile creep behavior of young concrete were systematically investigated by improving the set of testing apparatus designed formerly. Furtherly, baseing on the concept of equivalent time, the tensile creep behavior was evaluated and predicted by using the ZC model constructed by author based on rheology and experimental data. Finally, the effectivity and accuracy of ZC model was checked by experiment.The conclusions derived from the investigation are as follows: (1) The improved testing apparatus and method can be used to effectively evaluate the tensile creep behavior of high performance concrete at early ages under different curing temperatures and initial loading ages. (2) The Mechanical properties of HPC increased faster during the first 3 days, then decreased at later ages. The value of mechanical property increases with the temperature rises. (3) Modulus of elasticity in tension (Et) is about 8% higher than the modulus of elasticity in compression (Ec) of concretes under different curing temperatures. (4) For the same temperature, the later load was applied, the lower creep value and creep rate were. The difference in creep values and creep rates due to different initial loading ages become less visible with the time under load increases. (5) For the same loading age, the higher curing temperature, the lower creep value, and, the earlier load was applied, the more significant decline of creep value is.(6)It is suitable to discuss the effect of different curing temperatures on tensile creep behavior of concrete with equivalent time concept. The prediction formula of ZC model constructed basing on rheology can better describe the creep behavior of HPC at early ages especially when the initial loading age was earlier than 3 days.