Research On Carbonation Of Concrete Exposed To Heterogeneity Relative Humidity And Groundwater Environment

Carbonation resistance of concrete is one of the most important property of concrete durability.Environment conditions had obvious effect on the carbonation of concrete.Researching the carbonation in different environmental conditions is great significant to the analysis and evaluation of concrete durability.In the environment of heterogeneity relative humidity and groundwater containing corrosive carbon-dioxide,the accelerated carbonation tests are performed respectively.An analytical method is proposed to study the carbonation laws of concrete and the equipment of each test is developed.Carbonation depth of concrete specimensis measured and the relationship between the depth and each factor of cabonation are obtained by the tests.A multi-factor model of carbonation depth to predict the service life and design the durability of concrete is presebted.The main research work includes:1、An equipment to perform the accelerated carbonation tests in the condition of heterogeneity relative humidity is developed and an analytical method to study carbonation laws of concrete under the heterogeneity relative humidity environmentis proposed.The carbonation testcan be performed through this equipment effective and the carbonation depth of concrete specimensis analysized to reveal the carbonation laws of concrete under this condition.2、An accelerated carbonation device for the heterogeneity relative humidity environment is developed,and the accelerated carbonation tests in this environment are carried out for measuring the carbonation depth of concrete specimens at different carbonation ages.The impact of W/B,fly ash content,slag content and the relative humidity of environment on carbonation depth were studying,by which a multi-factor calculation model of concrete carbonation depth in this environment is developed by using the least squares method.3、A method for analysing the concrete carbonation laws in the environment of groundwater which contain erosive carbon dioxide is developed.According to the data of carbonation tests in this environment,the relationship between carbonation depth and it’s influence factors is proposed.A multivariate prediction model of carbonation depth in groundwater environment is found.4、The service-life prediction models of concrete structurein the heterogeneity relative humidity and the groundwater carbonation environment are proposed respectively,and a durability design method of concrete structure in these two environments is developed base on the multivariate prediction models presented.Some examples are given to demonstrate the reasonability and efficiency of the presented model and method.