Research On Quantitaive Design Of Carbonation Resistance Of Concrete And Its Service Life

Carbonation resistance of concrete is of paramount importance for concrete structures in common atmosphere environment with carbon dioxide. Traditional concrete preparation theory and methods usually use scheduled strength index for concrete mixture design, which is difficult to quantify the performance of concrete carbonation resistance. Therefore, a image analysis method of a comprehensive assessment of concrete carbonation coefficient based on the mechanism of concrete carbonation is presented in this paper. A multi-factor calculation model of concrete carbonation coefficient is establishment and a quantitative design method of high performance concrete durability is proposed. A comprehensive service life evaluation model of concrete under carbonation is put forword. This thesis’research work includes:1、A comprehensive image analysis of concrete carbonation coefficient is presented. This method using image analysis to analyze the entire cross-section of concrete carbonation region accurately and the carbonation coefficient is obtained based on area ratio of carbonation region, avoiding defects such as the subjectivity and poor accuracy of traditional method. An analytical tool for a comprehensive assessment of concrete carbonation is provided.2、The main factors that affect concrete carbonation in the concrete mix is got based on the single factor analysis of concrete carbonation coefficient. A multi-factor calculation model is estabalished based on our group’s carbonation test results of concrete with fly ash and slag and the collected concrete carbonation test data of relevant research group using the least squares regression analysis.3、The quantitative design method of high performance concrete anti-carbonation is proposed. The multi-factor calculation model of concrete carbonation coefficient is established. Then, the concrete mix that meets carbonation coefficient limits and concrete strength requirements is proposed. The preparation method of high performance concrete is put forward. And the prepared concrete is verified by strength and carbonation test. The multi-factor calculation model and the design method of concrete based on strength and anti-carbonation concrete is correct.4、Considering the environmental humidity, dry-wet circulation and CO2concentration in the accelerated test, combing the multi-factor calculation model, the comprehensive analysis model of the service life of concrete under carbonation is proposed. The analysis of concrete under different environmental grades is proposed.