喷射混凝土的室内检测方法及性能试验研究

采用自行设计的室内湿喷混凝土性能检测方法,开展喷射混凝土的力学、抗裂及施工性能试验研究。试验结果表明:复掺复合外加剂与粗纤维可提高喷射混凝土的抗压强度、弯曲韧性和抗裂性能;单掺复合外加剂和复掺外加剂与粗纤维的喷射混凝土,与围岩的轴拉粘结强度均在1.0 MPa以上,且复掺的强度较高;2组配合比的喷射混凝土回弹率分别为23%和20%,一次喷层厚度为22 cm和25 cm,复掺可增加混凝土的黏聚性,降低回弹率。由于场地及喷射仪器的限制,室内模拟试验的混凝土回弹率较现场高。

Study on Indoor Test Methods and Performance of Shotcrete

By using self-designed indoor test method,the performance of shotcrete were studied by blending nano-additive and crude fiber.The results showed that inorganic nano-additive and crude fiber could improve the compressive strength,flexural toughness and crack resistance of shotcrete.Axial bond strength of shotcrete with adjacent rock was larger than 1.0MPa either by doping nano-additive only or both nano-additive and crude fiber.The resilience rates of shotcrete with two mix proportions were 23% and 20%,and the shotcreting thickness were 22cm and 25cm.Doping both nano-additive and crude fiber can increase the cohesiveness and lower the resilience rate of shotcrete.The self-designed methods can also be used to compare the construction performance of different shotcrete.However,due to limitations of space and test equipment,the resilience rate in indoor test were higher than that in site test.The above test methods and results provided reference for indoor study of shotcrete and the development of technical standards.