为了研究隧道喷射混凝土单层衬砌碳化规律,采用快速碳化实验方法,研究了不同弯曲应力(0,0.25,0.5及0.75)作用下喷射混凝土及钢纤维喷射混凝土受拉区碳化深度变化规律。结果表明,喷射混凝土碳化深度经时变化规律服从Fick第一定律,碳化深度随着碳化龄期和弯曲应力的增加而增大。同实验条件下,喷射混凝土碳化深度小于普通混凝土,而钢纤维的加入进一步减小喷射混凝土同龄期碳化深度。在考虑弯曲应力影响系数、钢纤维影响系数及施工方式影响系数基础上对普通混凝土碳化深度预测模型进行修正,使其能够较好预测喷射混凝土碳化深度。
In order to research the carbonation of shotcrete single-layer lining in tunnel,the accelerator carbonation of shotcrete with and without steel fiber under bending stress which the ratios of flexural strength were 0,0.25,0.5and 0.75,respectively were studied.The carbonation depth of shotcrete obeys Fick's first law and increased with the carbonation age and bending stress improved.In the similar experiment conditions,the carbonation depth of shotcrete was small than ordinary concrete.Meanwhile,the carbonation depth of steel fiber reinforced shotcrete was much less than ordinary shotcrete at the same age.Based on the influence coefficients of bending stress,steel fiber and construction mode,the carbonation depth prediction model of ordinary concrete was modified.