Study On Transformed Ordinary And Recycled Hollow Steel Tube Concrete With Carbon Dioxide

For the advantages of concrete of its good function, it has been widely used. The structure of concrete practically can be seen everywhere in daily life. However, with the emission of industrial gas such as carbon dioxide, the environmental problem has increasingly been paid attention.The mainly function of carbon dioxide act on concrete has two aspects: firstly, carbon can improve the intensity of concrete; the second is its influence on the durability of reinforced concrete. The chief reason of improving intensity is that the carbonization reaction between carbon dioxide in air and the calcium hydroxide in concrete, and creates calcium carbonate that sediment. The concrete carbonization is a time-honored problem. The carbonization happens mainly for the process of neutralization reaction between the carbonic acid from carbon dioxide dissolved in water and the calcium hydroxide in concrete, and creates the calcium carbonate.The preceding scholars mainly considered about the concrete intensity, and regarded the concrete carbonization as one factor of influence on concrete intensity decrease. Because the concrete carbonization can decrease the PH in the concrete, and make the internal reinforcing steel bar rusty. So, how to effectively use the function of concrete carbonization act on concrete itself without making the reinforcing steel bar rusty has become the important point of this research. This passage has separately provided the finite element simulation and the pressure trial of the concrete carbonization。In this passage, as the innovation of this trial, it forms an enclosed space through welding the outer layer steel pipe of the hollow steel tube concrete and cover plate, in which the pressure can increase the diffusion coefficient of gas. So that, it can pick-up speed of carbon dioxide's entering the internal concretes. It can be regarded as the brand-new method to store carbon dioxide. This method can be applied in the actual project effectively. It can not only use the advantage of carbonization can improve concrete intensity, but only used as a new type of storage methods to store up industrial waste gas like carbon dioxide.The founding of finite element numerical model which based on the coupling equation of hot moisture set up by A.Saetta, mixing the pressure influence, it has surveyed the limited primary imitation with different influence factors. And then, based on the existing formula, we verified the outcome of numerical simulation, and combined the verified formula and the trial result. It can reach the relation equation between the intensity and all kinds of influence factors after carbonization.This question for study has separately done the comparative tests between general concrete and recycled concrete, in order to consider the relationship between the influence factors of carbonization and intensity improvement under different pressure and different time condition of carbonization.