Experiment Research On Concrete Durability Affected By Aggressive Carbon Dioxide In Groundwater Environment

When the concrete structure is in the groundwater with erosive carbon dioxide, it is confronted with one important problem of durability-neutralization, which may lead to the degradation or lose of the concrete structures and structure mechanics performance, and even worse, it may cause some catastrophic accidents. This paper is based on the fact that the present research about the neutralization of the concrete in erosive underground water is mainly on the aspect of the existing structure, and there are few prediction researches on the new structure; Besides, the mechanism analysis methods are mostly adopted in the pre-existing researches, and the experimental study combined with the practical projects are carried out less. Therefore, the research of the newly-built concrete structure in the underwater with erosive carbon dioxide is of great reference value and social economic benefits.This paper mainly includes the following parts:1.The paper introduces the significance of the research on the durability of the underground concrete structure and its research background. The paper states the present research on the concrete carbonation in the context of atmospheric environment, the durability of the metro concrete and the neutralization of the concrete in the context of erosive carbon dioxide. It also points out the problems in the current research on the neutralization of concrete.2.It gives a detailed account of the experiments plan adopted in this paper, and by the introduction of the process of in situ immersion, Carry out the in situ soak test.The paper carries out the cube compressive strength experiment of the concrete test cube before situ immersion, the carbonization test, the cube compressive strength experiment of the concrete test cube after situ immersion, and neutralization test as well as the microscopic test.3.The paper analyzes the relationship between time and the carbonation depth of the concrete test cube, and the influence on the carbonization of the mineral admixtures, home remedy cement contents, water-binder ratio, and water cement ratio as well as the compressive strength of the cube.4.Combined with the microcosmic images before and after the in situ immersions, the paper states the neuter mechanism and analyzes the influence on the neutralization of the concrete of the mineral admixtures, home remedy cement contents, water-binder ratio, and water cement ratio as well as the compressive strength of the cube. It also analyzes the exponential relation between the neutralization depth and the carbonation depth for28days.5.This paper summarizes the main research work and forecasts the research on the neuter study in the future.This thesis is financially supported by National Natural Science Foundation of China(51078334)and National Science Foundation of China(50925829).