Fresh Concrete Anti-carbonation Research Based On Simulation And Fast Carbonization Experiment

Carbonation is one of the most important elements that influence the structureendurance which had entered a brand new era as the development of computertechnology since the21th century. Concrete structure alkalinity reduce caused bycarbonation was the main reason that initiate reinforcement corrosion which reducedthe stress section itself on the one hand and gave rise to corrosion crack as well as thelessen of the adhesive between the steel and concrete structure on the other hand, andfinally affected the endurance of the concrete structure.It’s a real attributes of carbonation process that CO₂diffuses through theconcrete structure of which alkalescence and porosity is the theoretical foundation andmaterial conditions for carbonation procession. Based on the mechanism ofcarbonation procession and principle of mass conservation carbon-based element, wededuced the governing equation of carbonation procession and does numericalanalysis by finite element analysis method, calculated the coefficient diffusion matrixof CO₂, carbonization reaction matrix and shape function matrix, and finally receivedto the basic approach of finite element analysis.In this paper we analyzed about the similarity between the carbon dioxide inconcrete carbonation process and the heat transfer in heat conduction process andproceed a numerical simulation on retaining wall with general FEM softer wareANSYS compared with the results of rapid carbonization experiment. Moreover wehas done the sensitivity analysis of the factors about Temp, humidity, concentration ofcarbon dioxide and bearing capacity situation which all influenced the diffusionvelocity of carbon dioxide and carbonation reaction rate of concrete structure.We have done experiment research both of shadow surface display and improvemix proportion which aimed to enhance the anti-carbonization capability of freshconcrete structure, simulated the procession of fresh concrete with shadow surfacedisplay by numerical simulation and acquired the discipline of its carbonization.It shows that we can realize the numerical simulation of fresh concretecarbonization with the research of control equation of concrete carbonation and thenumerical analysis of carbon dioxide diffusion in the concrete structure.