Study On The Fire Resistance Properties Of Concrete Structures Under Sodium Fire

To study the fire resistance of concrete structures and the effect of structural protection measures under the action of sodium fire,it is great importance to the structural design of our country's sodium-cooled fast reactor nuclear island plant.This paper takes four different thickness of concrete plates and three different protective measures of reinforced concrete cells as the research object,and establishs two experimental platforms of sodium fire.By measuring and collecting the temperature and strain of concrete specimens in the experiment,change rules of temperature and stress of each specimen under sodium fire are analyzed.The specimens were simulated by ABAQUS,and verifying the feasibility of finite element software for sodium fire analysis.Finally,the specimens are sampled by drilling core after sodium fire,and measuring the compressive strength of the core samples.Main contents of this paper are as follows:(1)Based on experimental platforms of concrete erosion by sodium fire,we carried out sodium fire experiments on four thickness of concrete plates,we've got fire damage situation of each plate,and distributions of temperature and stress.The results show that when the spray of liquid sodium is over 1.5kg,the fire surface of concrete plate will have an erosion damage that is about 1cm deep;at the same time,the maximal compressive stress of each plate is not exceeding 14 MPa,and the maximum temperature of 300 mm thick concrete plate's bottom measuring points is only 38?,and the 300 mm thick concrete plate has good thermal insulation effect in sodium fire.(2)Based on sodium fire experimental platforms of the most adverse room,we carried out sodium fire experiments in three reinforced concrete cells,through the analysis of cells' temperature and stress,we got the thermal insulation effect of the indoor space protection measures.The results show that when the protective measures of the wall are 2mm thick carbon steel plate and 10 mm thick rock wool board,which can effectively isolate the heat from the sodium fire,and the maximum temperature in the wall is limited to about 45?;when the protective measures of the wall is increased to 6mm thick carbon steel plate and70 mm thick aluminium silicate wool board and 30 mm thick rock wool board,not only the highest temperature of the wall is reduced to below 34?,but also the thermal stress of the wall is limited to-1~1MPa.(3)The concrete specimens of sodium fire experiment are modeled and analyzed by ABAQUS,and the numerical simulation is compared with the experimental results.The results show that in the numerical simulation results,not only the heated and forced condition of cells' left and back walls,but the temperature distribution of plates are found in good coincidence with experimental data.(4)The specimens are sampled by drilling core at the end of the sodium fire experiment,then the compressive properties of the cylinder is tested.The results show that compared with control group,the compressive strength of concrete has not changed obviously in the left and back walls of each cell,but the compressive strength and peak strain of 300 mm thick plate are decreased by 28% and 24% respectively.