骨料坚固性对喷射混凝土性能影响分析

Analysis of Influence of Aggregate Firmness on Shotcrete Performance

新疆某引水隧洞工程的主料场在勘察时发现部分骨料坚固性指标远超规范要求,因此开展骨料坚固性对喷射混凝土性能影响研究。采用4种坚固性不同的砂石骨料配制喷射混凝土进行力学试验和耐久性试验,结果表明:砂子坚固性值≤16.8%,豆石坚固性值≤25.3%,对喷射混凝土拌合物性能没有影响,对轴向抗拉强度、抗渗性、抗冻性、抗硫酸盐侵蚀性影响不大,对抗压强度和抗氯离子渗透性能有一定影响。当砂子和豆石坚固性分别达到13.2%和20.1%时,喷射混凝土28d抗压强度降低25.8%,氯离子扩散系数增大38.7%。

During the investigation of the main material yard of a diversion tunnel project in Xinjiang,it was found that the firmness index of some aggregates exceeded the standard requirements,so the influence of aggregate firmness on the performance of shotcrete was studied in this paper.The mechanical test and durability test of shotcrete prepared by four kinds of sand and stone aggregate with different firmness are carried out.The results show that:Sand firmness≤16.8%,beanstone firmness≤25.3%,has no effect on the performance of shotcrete mix,has little effect on the axial tensile strength,impermeability,frost resistance,sulfate corrosion resistance,compressive strength and chloride ion penetration resistance have a certain effect.When the sand and stone firmness reached 13.2%and 20.1%,respectively,the 28d compressive strength of shotcrete decreased by 25.8%,and the diffusion coefficient of chloride ion increased by 38.7%.