Research On The Compressive Fatigue Properties Of HSC After Different High Temperature Process

With the rapid economic development,high-strength concrete materials are widely used in modern buildings,such as CCTV Cultural Center,Shenyang Royal Wanxin Hotel.However,the building structure of the fire problem has become increasingly prominent,the building suffered a fire and other high temperature,the concrete structure will produce a series of physical and chemical changes,resulting in structural degradation by varying degrees,especially high temperature concrete burst,with a sudden,the damage will exacerbate the structural damage.For engineering structures as the Television Cultural Centre using high strength concrete materials,sometimes subject to fire or other high-temperature process,and sometimes suffer from earthquakes and other repeated loads.At present,it is not yet possible to estimate the residual seismic capacity or anti-fatigue performance of the concrete structure in the field engineering,leading to the final evaluation conclusion and the hidden danger of the reinforcement scheme.Therefore,it is necessary to study the mechanical properties and fatigue damage of high strength concrete after different high temperature.In view of the domestic and foreign research status and existing problems on the mechanical properties and fatigue damage HSC,in this paper,by comprehensive means of champer type electric resistance furnace,electro-hydraulic servo universal testing machine,electro-hydraulic servo fatigue testing machine,the resulting performance changes of the HSC after different high temperature process(mainly fatigue performance)are analyzed.The relationship between the high temperature process and the fatigue damage of high strength concrete was established by the compressive strength test and fatigue test of high strength concrete subjected to high temperature.The scientific method of studying the relationship between high temperature history,mechanical properties and fatigue damage of high strength concrete was established.The mechanical properties and fatigue damage of C60 high strength concrete after different high temperature process were studied,including the remaining strength,mass,elastic modulus,peak strain,fatigue life,fatigue strain,residual strain and fatigue damage after different high temperature.Then,the mechanical properties of HSC were compared with those of ordinary concrete.It was found that HSC had obvious different characteristics to ordinary concrete in the range of 500?.HSC will become rapid warming and burst,much lower than the ordinary concrete 800? burst temperature,showing more brittle.Correlation analysis of temperature process and mechanical properties respectively,on the basis of the good correlation,mathematical models of the relationship between the temperature process with the residual strength,the elastic modulus,the peak strain,the fatigue life,the fatigue strain,the fatigue residual strain and the fatigue deformation modulus.Using the fatigue deformation modulus ratio and the relative residual strain as the damage variables,the relationship between the high-temperature concrete,the mechanical properties and the fatigue damage is established.The model can not only scientifically and quantitatively describe materials of the mechanical properties under different high temperature process,and accurate quantitative high temperature process and fatigue damage of the relationship.