Study On Creep Properties Of Fly Ash Concrete Under Sulfate Attack

Creep as one of the influencing factors of concrete durability,is the deformation of concrete structure with time under load.This characteristic is affected by concrete performance,load,environmental conditions and other factors.Concrete is also widely used in the construction of water conservancy projects.Compared with ordinary engineering buildings,the environmental factors faced by hydraulic engineering buildings are more complex.Water conservancy buildings in coastal areas and inland areas with high content of erosive substances(such as salt lakes)suffer from erosion for a long time,which seriously affects the durability of concrete.In sulfate environment,the creep of fly ash concrete corroded by sulfate involves multiple factors of physics chemistry mechanics,and the mechanism is very complex.Therefore,the research on the performance of fly ash concrete in corrosive environment can play an effective role in practical engineering,and it is also of great significance to the creep performance of concrete.In this paper,the creep law of fly ash concrete under sulfate attack is studied theoretically and experimentally.The main research contents are as follows:(1)Based on the analysis results,it is found that the concrete creep increases with the increase of sulfate solution concentration,and fly ash can inhibit the concrete creep,and the creep decreases with the increase of fly ash content;(2)According to Fick's second diffusion law,based on the diffusion rate and depth of sulfate ion in fly ash concrete,the sulfate ion diffusion model and the damage deterioration model of fly ash concrete are established,and their accuracy is verified by test data;(3)On the basis of the above research,the B4 model based on consolidation theory is modified,and combined with the damage theory of concrete,the creep calculation model of fly ash concrete under sulfate attack is established.Through the comparison of test data in this paper,its feasibility is verified;(4)Through regression calculation,the creep design formula of fly ash concrete under sulfate attack is established,and compared with the test data,the feasibility of the formula is verified.