摘要
依托武九高速公路高楼山长大隧道实体工程,对比研究了西北地区冬季低温干燥养护条件下喷射混凝土的力学性能及长期耐久性能,并采用SEM观察了喷射混凝土碳化损伤区域及碳化产物的微观形貌。结果表明:西北地区隧道喷射混凝土受冬季低温干燥养护环境影响,早期抗压强度明显下降,且90 d强度提高缓慢。低温干燥养护环境会造成喷射混凝土早期干燥收缩增大,同时造成喷射混凝土长期抗冻性明显下降,快冻法循环次数小于200次。西北地区喷射混凝土实体结构的碳化侵蚀作用发展较早,28 d时喷层结构的碳化深度在4.0 mm左右,低温干燥养护条件更加剧了喷射混凝土的碳化损伤程度,碳化产物碳酸钙易富集在结构缺陷处,以片状堆积形式生长。
According to Gaoloushan long tunnel with solid structure in Wujiu highway,the mechanical properties and durability of long tunnel shotcrete under cold drying environment in Northwest China were studied contrastively.Also,micro-morphology of damaged area and carbonification products of shotcrete under carbonification effect were analyzed by SEM.Results shown that early age mechanical strength of shotcrete was reduced obviously with cold and drying curing environment and 90 d strength of shotcrete improves slowly.Cold and drying curing environment will increase the early drying shrinkage of shotcrete,and significantly reduce the long-term freezing resistance of shotcrete.The cycle times of quick-freezing method is less than 200.Early carbonation effect of shotcrete in tunnel solid structure was observed,with carbonation depth measured as over 4.0 mm when curing age reached 28 d,the carbonation damage level of shotcrete was impelled with cold and drying curing environment.The carbonation products,calcium carbonate,grew and gathered around defect area of shotcrete with plate-like form.
作者
张付军
曾鲁平
ZHANG Fujun;ZENG Luping(Gansu Changda Highway Co.Ltd.,Lanzhou 730000,China;State Key Laboratory of High Performance Civil Engineering Materials,Jiangsu Sobute New Materials Co.Ltd.,Nanjing 211103,China)
出处
《新型建筑材料》
2021年第11期120-124,共5页
New Building Materials
