冲击荷载作用下速凝剂对喷射混凝土破坏强度研究

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

    • 摘要: 为研究喷射混凝土的动态力学性能,采用74 mm分离式霍普金森压杆(SHPB)装置,对掺入占胶凝材料0%、2%、4%、6%速凝剂的喷射混凝土进行不同养护龄期RMT静态力学试验和冲击试验。对比分析表明:静压条件下,喷射混凝土随着龄期的增加,强度显著增大,喷射混凝土早期强度随速凝剂掺量增加而增大,中后期强度与之相反;冲击荷载作用下,喷射混凝土动态强度增长规律与静态强度相似,但动态强度是静态强度的1.1~1.4倍,结合试件破坏状态与动态应变发现早期喷射混凝土,表现出黏弹性,养护7 d以后表现出脆性材料的性质;当速凝剂掺量为胶凝材料2%时,喷射混凝土总体性能最好。

       

      Abstract: 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.

       

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