A Study On Sulfuric Acid Corrosion Performance Of Fly Ash Cement Concrete And Erosion Test Of Fly Ash Cement Mortar

Durability is a common issue of modern concrete structures since it is a main reason for structure failure and the decease of period of life cycle. With the dramatic increase of sulfuric acid-based acid rain in the development of industry and city, there is increasing corrosion of structure caused by acid rain. Studying durability of concrete structure under the erosion of dilute sulphuric acid, therefore, has both theoretical significance and meaning of applying to practice.The second chapter of this dissertation explain some main evaluate index, theory model of mutual action.and test design of structural erosion by acid and dilute sulphuric acid rain. For the main index, the change rate of titration acid consumption is used to express the acid consumption rate of the model based on the dissolving reaction model of consistency boundary. which can provide diffusion coefficient of corrosion reaction indirectly. In order to measure acid consumption rate in different cases by titration acid method. some common test designs and data processing methods are summarized. by which an efficient test design method and data processing method can be chose.To study the anti-erosion performance to dilute sulphuric acid. some long time immersion tests are conducted for fly ash cement mortar and fly ash cement concrete under different conditions. respectively. The third chapter discusses the long term immersion test of mortar. Using titration acid method, the erosion rate of each test is obtained to calculate diffusion coefficient, which can show characteristics of erosion action. Combining partial correlation theory, diffusion coefficient and correlativity between erosion rate and some parameters such as water-to-cement ratio, fly ash additives amount and mobility are studied for some different levels of these parameters.Based on the study of chapter three, the fourth chapter adopts uniform design to consider more parameters. The long time immersion test of fly ash cement concrete is also conducted. The acid consumption rate is calculated by titration acid method, then diffusion coefficient of corrosion process is obtained. By nonparametric regression technique. the relationship between diffusion coefficient and water-to-cement ratio, fly ash additives amount and mobility is obtained.To study erosion-corrosion effect of dilute sulphuric acid on concrete, a test equipment to simulate indoor speed-up erosion is introduced in chapter five. Using this equipment, some different speeds of surface corrosion are simulated. The diffusion coefficient is calculated by the rate of assuming acid and the erosion law of dilute sulphuric acid on mortar is analyzed for some special conditions.This thesis is partly sponsored by the Natural Science Foundation of China(Grant No.:51078175) and the Natural Science Foundation of Yunnan Province(Grant2008E038M).