Research On Performance Of Sea Sand Concrete -filled Steel Tube Corrosion Resistance

Because of the lack of river sands, sea sand has been more and more applied to the industrial and residential buildings. However, the chloride ion contained in sea sands has rather intense catalysis to the corrosion of steel. The "sea sand houses" appeared around the coastal areas have caused a serious threat to human living, which has caused the intense attention of people. Thus our country has published corresponding codes to restrain the range of sea sand application, in order to manage its utilization.After analysis the structure of concrete filled steel tube is a combination structure of steel tube and concrete. The element of steel tube concrete is different from reinforced concrete, which is beneficial in the field of sea sand. When the reinforced concrete elements suffer from the corrosion of the sea sand, moisture and oxygen mixed in the concrete keep the process of corrosion reaction working. The concrete cracks by corrosion reaction intensifying, and the corrosion reaction intensify increasingly by exposing rebar in the air. While reinforced concrete elements suffer form the corrosion of the sea sand, the corrosion reaction will disappear, because the concrete is in hermetic environment, which make the necessary moisture and oxygen not enough.Based on the idea the thesis explores the sea sand on the building of the steel corrosion in principle; The thesis analyzes the corrosion current density of inner steel tube, by the testing samples of sea sand CFST, both in the situation of air proof and that of moisture increasing permeation, and analyzes factors primary and secondary function of the corrosion in different experimental conditions in each stage; By means of the diffuse mode of COMSOL software, the corrosion reaction of sea sand CFST has been represented in a real situation by simulating the flux, and forecast the corrosion degrees many years later.Based on the testing and simulation analysis mentioned above, it is impossible that the sea sand can be used in CFST. And finally concludedthat:(1)When reinforced concrete reinforced are corroded oxygen and water can get added from the air, however when steel corrosion caused by sea sand in the concrete filled steel tube, oxygen and water is less and less, and the corrosion rate slow down; (2) Through the experiment know that the corrosion in different conditions, in the different stages oxygen, water, chlorine ion control corrosion effect respectively;(3) It comes to a conclusion that there is almost no negative effect on the bearing capacity if the sea sand is used in CFST.