Study On The Effect Of Lithium Slag On The Adsorption Of Chloride Ions In Concrete

The history of the development of reinforced concrete structure is less than two hundred years,but it is widely seen all over the world,but it is found in coastal cities.However,the development of high chlorine natural environment such as saline soil area in Northwest China is seriously restricted by durability problems such as steel bar corrosion.How to extend the life of reinforced concrete building is one of the most difficult problems faced by civil engineers at present.It can delay the diffusion rate of chloride ions,and the stronger the chloride adsorption ability of concrete is,the longer the service life of reinforced concrete buildings is.Therefore,it is of great significance to study the adsorption properties of chloride ions in concrete with active mineral powder for the life prediction and durability of reinforced concrete buildings.In this paper,the chlorine adsorption properties of lithium slag concrete under high chlorine environment were studied by natural diffusion method and wet and dry cycle method.The chloride ion concentrations of lithium slag concrete specimens and mortar specimens under different conditions were determined by chemical titration with reference to JTJ270-98.The influence of the strength of the specimen,the content of lithium slag,the age of erosion,the concentration of chlorine salt,the depth of permeation,the humidity of the environment,and so on,on the adsorption properties of lithium slag concrete under the condition of dry and wet alternate environment and natural immersion environment were discussed.The main contents and conclusions are as follows:(1)Lithium-slag concrete specimens in natural immersion environment: in three kinds of high concentration NaCl erosion solution,C20C30C30C40C60,the cement used in each strength grade is replaced by the quality of Li slag of 0% 1010% and 20% Li slag,respectively,in three kinds of high concentration NaCl erosive solution,and the cement used in the water cement ratio of each strength grade is replaced by four kinds of strength grades,such as C20C30,C40C60,and so on.The erosion was carried out for 5 days,10 days,20 days and 40 days.The effects of lithium slag content,strength grade,erosion age,chloride concentration and diffusion depth on the adsorption performance of chloride ions were obtained.With the increase of lithium slag substitution amount,the adsorption energy of chloride ions of the sample was obtained.The force decreases gradually with the increase of lithium slag,the adsorption capacity of chlorine ion decreases with the increase of the strength grade,and increases with the increase of diffusion depth.The adsorption capacity of chloride ions of lithium slag concrete is increasing.Under the condition of different chloride concentration,the adsorption capacity of lithium slag concrete with different strength accords with the quadratic function relation,and with the increasing of erosion time,the adsorption capacity of chloride ion of lithium slag concrete is in accordance with the quadratic function.The adsorption capacity of lithium slag concrete with different strength is weakening.(2)Lithium slag concrete specimens under the action of dry and wet cycles: the relative humidity of dry and wet alternating action is 40,60 and 80,respectively.The system of wet and dry alternation is as follows: spray NaCl solution 20 min drying for 3 h and 40 mins,and every 4 h for a cycle period.The other conditions are the same as the natural immersion environment.At the same time,the influence of the strength grade,the amount of lithium slag,the age of erosion,the concentration of chlorine salt,the depth of permeation and other factors on the adsorption performance of chloride ion were obtained: the adsorption capacity of chlorine ion at relative humidity 80,With the increase of the content of lithium slag,it tends to decrease,and then increases first with the increase of strength grade.The adsorption capacity of the sample increased firstly and then decreased with the increase of chloride concentration,and the adsorption capacity of chlorine ion at 60% relative humidity increased gradually,while the adsorption capacity of the sample increased gradually with the increase ofthe permeation depth,and the adsorption capacity of the sample increased firstly and then decreased with the increase of chloride concentration.With the increase of the content of lithium slag,the content of lithium slag increased first,then decreased,and gradually increased with the increase of strength grade,and the adsorption capacity decreased gradually with the extension of erosion age.With the increase of permeation depth,the adsorption capacity of chloride ions increased at first and then decreased with the increase of chloride concentration,and the adsorption capacity of the sample increased with the increase of lithium slag content at relative humidity of 40.With the increase of the strength grade,the adsorption capacity of the lithium slag concrete gradually decreased with the age of erosion,and gradually increased with the increase of the depth of the permeation.With the increase of the concentration of chlorine salt,the trend of the increase was first increasing and then decreasing.