Study On Dynamic Performance Of Concrete After Freezing-Thawing Cycle

With the rapid development of national infrastructure,the number of engineering projects in cold areas is increasing,and there are more and more concrete buildings in these areas.Therefore,more and more attention has been paid to the effect of freezethaw cycles on the durability of structures.In-depth research on the effects of freezethaw cycles on concrete It is very necessary to have the influence of;in addition,the actual building may be impacted by dynamic loads,such as ship strikes,dams subjected to dynamic water pressure,etc.At present,there are few studies on the dynamic mechanical properties after freezing and thawing.Therefore,this paper studies,analyzes and summarizes the dynamic properties of concrete after freezing and thawing.The main contents are as follows:(1)The maximum freeze-thaw cycles are 150 times and 125 times for the cylindrical specimen(Φ100×200mm)and the round cake specimen(Φ70×35mm),and every 25 freeze-thaw cycles The thawing cycle is a working condition;the test phenomenon is observed during the test,and the relationship curve between the freezethaw cycle and its relative dynamic elastic modulus,mass loss rate,porosity,etc.is obtained through the freeze-thaw test;and through the static test,the analysis The effect of freeze-thaw damage on the static mechanical properties of concrete.(2)Through the SHPB impact compression test,the dynamic stress-strain curves under different degrees of freeze-thaw damage were obtained,the strain rate effect after freeze-thaw was studied and analyzed,and the dynamic compressive strength dynamics of different freeze-thaw cycles were given.Fitting formula for magnification factor.(3)The dynamic tensile properties of freeze-thawed concrete were studied and analyzed by INSTRON impact splitting test.The dynamic tensile properties of concrete with different degrees of freeze-thaw damage are studied and analyzed,and the failure modes of concrete under different freeze-thaw damage are obtained through high-speed camera recording.In this paper,the basic physical quantities and mechanical properties of concrete antifreeze resistance under different freeze-thaw cycles are studied and analyzed from the two aspects of static force and dynamics,and the dynamic failure form,strain rate effect and stress strain curve of concrete materials after freeze-thaw cycle are analyzed,which provides certain ideas for the future research of concrete materials,and also provides certain thinking and inspiration for the future numerical simulation of dynamic properties on concrete components after freeze-thaw cycle.