Study On Bearing Capacity Of Reinforced Concrete Beams Under Carbonation,Freeze-thaw And Chlorine Ion Coupling

The emergence of cement has led to great development of reinforced concrete structures.It is common for concrete structures that have always been considered durable to be damaged due to damage during service.Now,a large number of concrete structures have been built and the reinforcement of concrete structure has spent a large amount of funds.Therefore,the durability of reinforced concrete structures is urgently studied.This paper is based on whether reinforced concrete bridges are sprayed with ice-drenched salt in the cold area.Through the multi-functional environmental laboratory of Chang`an University,carbonation and freezing-thawing cycles coupling experiment was performed on reinforced concrete beams under stress and without load,as well as carbonization,freeze-thaw cycle,chloride ion coupling test.Efforts were made to simulate whether or not the main beam of concrete bridges of various types,such as reinforced concrete bridges and pre-stressed concrete bridges,will be eroded by the severe cold area in the deicing salt environment.After the test,the bearing capacity of each was tested and simulated,analyzed and verified by ANSYS.Finally,a time-varying attenuation model and a stress correction model for the bearing capacity and material of reinforced concrete beams under corrosive environments were obtained.The main conclusion of this paper is as follows: The load-bearing capacity and material's time-varying attenuation model and stress correction model of reinforced concrete beam under the coupling of carbonization-freezing and thaw are established.The load-carrying force and material stress correction model of reinforced concrete beam under the coupling of carbonation-freeze-thaw-chloride ion are established.When the beam is under tensile stress,corrosion will be promoted,and compressive stress will inhibit corrosion,but when the compressive stress is too large,it will have a negative effect on the concrete beam.Cracks on the underside of reinforced concrete beams under the coupling of carbonization-freezing-thawing and chloride ions are all generated at the stirrups and the test beams are fractured similarly with weakly-reinforced beams.