Cyclic Impact Dynamic Characteristics of Sprayed Engineered Cementitious Composites for Reinforcement
The traditional engineered cementitious composites (ECC) have problems of high cost and large shrinkage,and there is a lack of research on cyclic impact dynamic characteristics of sprayed engineered cementitious composites (SECC) for reinforcement.Based on this,the split Hopkinson pressure bar was used to carry out cyclic impact test for SECC under compression and splitting.The stress-strain curve,deformation and energy evolution characteristics,fatigue damage and failure characteristics were systematically analyzed.The variation rule of each physical quantity was explored in detail,and the prediction model of mechanical properties was established.The result indicates that under cyclic compression,the conversion rate of reflection energy continues to increase,while the conversion rate of absorption energy and transmission energy continues to decrease.Compared with the first impact,the conversion rate of absorbed energy is reduced by 63.94% at the final destruction.Under the cyclic splitting,the conversion rate of reflection energy maintains upward trend,while the conversion rate of transmission energy and absorption energy maintains downward trend.After 3 cycles of splitting,compared with the first impact,the absorption energy conversion rate at the final failure is reduced by 0.72%.The deformation damage and energy damage of specimen increase with the increase of cyclic impacts.The damage variables based on energy characteristics are generally higher than those with deformation characteristics.When the two sorts of cyclic impact tests are damaged,the energy damage variables increase by 913.19% and 222.89% respectively.SECC helps to provide the required flexible deformation space for the reinforced layer under impact stress,and also provides flexible buffer space for dynamic energy release.