| 摘要: |
| 为研究公路隧道衬砌在酸性气体环境和围岩荷载作用下的碳化特性，开展了硝酸侵蚀与弯曲应力共同作用下的混凝土快速碳化试验，测试分析了混凝土的碳化深度、碳化物质含量和微观结构.结果表明：硝酸和弯曲应力均能促进混凝土的碳化；随着硝酸浓度和弯曲应力水平的增加，混凝土的碳化深度增大，碳化物质含量减少；硝酸会消耗水化产物，削弱CaCO3对孔隙的填充，形成微裂缝，最终增大混凝土的孔隙率；弯曲应力促使微裂缝发展形成受拉裂缝，并与碳化协同形成微裂缝. |
| 关键词: 混凝土 碳化 硝酸侵蚀 弯曲应力 微观分析 |
| DOI：10.3969/j.issn.1007-9629.2023.01.008 |
| 分类号:TU528 |
| 基金项目: |
|
| Concrete Carbonation under Nitric Acid and Bending Stress |
|
ZHOU Zhijun, WANG Hao, TIAN Yeqing, ZHANG Zhipeng
|
|
School of Highway， Chang'an University， Xi'an 710064， China
|
| Abstract: |
| To study the effect of acid gas and bending stress on the carbonation durability of highway tunnel lining， the accelerated carbonation test of concrete under the combined action of nitric acid erosion and bending stress was carried out， and the carbonation depth， carbonation substance content and microstructure of concrete were tested and analyzed. The results show that both nitric acid and bending stress can promote the carbonation of concrete. With the increase of nitric acid concentration and stress level， the carbonization depth increases and the content of carbonized substances decreases. Nitric acid erosion consumes alkaline substances and weakens the filling effect of CaCO3 on pores， forms microcracks and increases porosity. The bending stress makes the microcracks develop further， form tensile cracks， and the microcracks are formed in coordination with carbonation. |
| Key words: concrete carbonation nitric acid erosion bending stress microscopic analysis |
