| Concrete carbonation is always regarded as an important cause of deteriorating in service-life performance of reinforced concrete structure (RC), and the CO2 concentration increased attracts more attention on the neutralization of concrete. Researches oncarbonation of concrete structures play an important role in accurately predicting the concrete structure service life. With the development of the high-performance concrete materials, fly ash and other mineral admixtures, as an important component of concrete, are widely used in civil engineering. Unfortunately, more and more test results show that compared with OPC, fly ash concrete, especially large volume fly ash concrete are not good at anti-carbonation. While in this main line, the main research works are as follows:From the viewpoint of mass diffusion and reaction as well as kinetics of chemical reaction and based on one-dimensional diffusion equation, the author (i.e. me, the below is the same) established a series of Partial Differential Equations (PDES), developed their numerical solution by Matlab according to the mass conservation of materials that can be carbonized and simulated the diffusion and reaction of carbon dioxide in concrete.Based on the theory of aggregate grading and probability density function of porosity of concrete, firstly, the author obtained the random delivery of aggregate and porosity in concrete by Matlab ("Numerical Concrete"), simulated the diffusion of carbon dioxide in Numerical Concrete by Abaqus (in which the porous matrix was produced with the methods of Random Walk, Voronoi and Random Delivery), and compared the simulation results with the results of the one-dimensional equation.Accelerated carbonation tests of fly ash concrete were carried out to study the carbonation depth varying with the amount of fly ash and concrete curing methods, and the accelerated carbonation technology was used in the curing process of fly ash concrete to makes up its disability of lack of anti-carbonation. |
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