Study On Bearing Capacity Of Reinforced Concrete Beam Under Freeze-thaw Cycles

The freeze-thaw damage is one of the most extensive and the most common form of concrete deterioration, Freeze-thaw cycle effect produce the damage layer of concrete from the outside to the inside, eventually lead to the failure of concrete. The concrete structures in northern cold region are influenced by both load and freeze-thaw.freeze-thaw damage have a dramatic effect on the durability of the structure, the structure and component of the bearing capacity, deformation and ductility degenerated.This topic research the bending and shear capacity degradation law of reinforced concrete beams in freeze-thaw environment, for appraising of the durability of concrete structure under freeze-thaw environment is of great significance.In this paper, Study on Bearing Capacity of Reinforced Concrete Beam under Freeze-thaw Environment was conducted based on the combination of laboratory test method, theoretical analysis and Finite element analysis of numerical simulation. Do research for study the flexural bending capacity and shear bearing capacity of reinforced concrete beam under freeze-thaw environment. The main contents in this paper are as follows:( 1) Using air-freezing and air-thawing mechanism of freeze-thaw simulates experimental method. Do the freeze thaw durability test of full-scale reinforced concrete beam. Design of freeze-thaw cycles followed by zero, 50 times, 100 times, 150 times.After the completion of freeze-thaw, do the static loading test for experimental beams which under different freeze-thaw cycles. analysis the bearing capacity degradation law of the test beam under the freeze-thaw cycles.(2)Based on the material experimental data of concrete after freeze-thaw what our team got and considered the freeze-thaw damage of concrete section, Then obtainedfunction relation between ascending control parameter a, descending control parameter b of the complete stress-strain curve of concrete and freeze-thawing cycles N. The concrete section is divided into the damage layer and non damage layer two parts, using the assumption of strain coordination to determine the peak strain and peak stress of damage layer and non damage layer.( 3) Using ABAQUS finite element analysis software, the concrete section of full-scale RC beams divided into the damaged layer and non damage layer. Do numerical analysis research on reinforced concrete beam’s flexural bearing capacity.Combined with the test results and then analysis the flexural bearing capacity degradation. law of reinforced concrete beam under freeze-thaw cycles.To move forward a single step, do numerical analysis research on reinforced concrete beam’s shear bearing capacity, considering the shear span ratio, stirrup ratio and freeze-thaw cycles those three factors, analysis the shear bearing capacity degradation. law of reinforced concrete beam under freeze-thaw environment. And established the shear bearing capacity degradation model, and verified the model.