Study on Damage Strength of Sprayed Shotcrete with Accelerating Agent Under Impact Load

To study the dynamic mechanical properties of shotcrete, a 74 mm split hopkinson pressure bar (SHPB) device is used to conduct RMT static mechanical test and impact test on the shotcrete with 0%, 2%, 4% and 6% accelerating agent added into the cementitious material at different curing ages. The comparative analysis showed that: under static pressure conditions, the strength of shotcrete increases significantly with age, and the early strength of shotcrete increases with the addition of accelerator, but, in the middle and later stages, the strength is opposite; under the impact load, the dynamic strength of sprayed concrete increases similarly to the static strength, but, the dynamic strength is 1.1 to 1.4 times of the static strength. The early shotcrete is discovered by combining the failure status of the specimen with the dynamic strain. The viscoelastic properties showed that the properties of brittle materials were exhibited after 7 days of curing. When the amount of quick-setting agent was 2% of cementitious material, the overall performance of shotcrete was best.