Compression Behavior Of GFRP Reinforced Concrete Columns Under Load And Environment

The new type material,fiber reinforced plastic—— FRP,which has the quality of light,high strength and Electromagnetic neutral and corrosion resistance,it is becoming a new generation of civil engineering structure materials.FRP bar is used to replace steel corrosion reinforcement can solve the fundamental problem.With FRP bar widely used in practical engineering,we must be fully research of the material performance.In this paper,the author produced 16 GFRP reinforced concrete columns,they were divided into two groups,one group is used to do full immersion test,and the corrosion solution is divided into the alkali solution and artificial seawater corrosion solution,four columns of concrete were placed in each solution of full immersion test,which cycled for 30 days,lasted 120 days.In view of the concrete columns actual environment,another group soaked the artifacts in two kinds of corrosion solution and continued to load them at the same time,the test cycle is 30 days,lasted 90 days.Observe the corrosion phenomenon and study the corrosion mechanism.Through compression tests research before and after corrosion concrete ultimate load-carrying capacity,failure pattern and components of various properties of concrete,GFRP reinforcement and stirrup.Experimental results show that for a single immersion test,with the increase of corrosion time,corrosion of concrete columns are increasingly serious,ultimate bearing capacity descend.Component surface dissolve out crystal precipitation,stirrups corrode obvious,concrete surface rise sand phenomenon.GFRP reinforced concrete column with the increase of load until both linear relation with the basic of the damage.Concrete column failure pattern can be divided into axial compression destruction and fracturing.But with the increase of immersion time,fracturing occurrence probability increase.This is mainly due to weak positions such as solution for variable cross-section caused by corrosion.With the increase of corrosion time,pillar longitudinal displacement increases,after 120 days,stirrup strain variation is the largest,because the concrete cover is thinner,corrosion ion permeate into the concrete member,it is easy to make the most of the lateral stirrup corrosion.Strain of concrete is the largest in compression test.For coupling GFRP reinforced concrete columns under the action of environment and load,bearing capacity declined slightly in alkali solution.GFRP reinforced concrete column after 120 days on the corrosion of longitudinal displacement and the load strain curve,it can be seen that the curve of constant load slope than the curve of constant load.Loading stiffness of the axis of the column is greater than otherwise load stiffness of the axis of the column.In artificial sea water solution bearing capacity reduce after rising first,GFRP rebar and concrete and the stirrup strain are larger than a single corrosion condition.Constant load of the load displacement curve slope is larger than not load,this is mainly because of the GFRP reinforced concrete column before making compression performance test,what has gone into the early stage of the load.Continuous load and environment under the action of coupling corrosion and pressure test in the process,Using the fiber grating for continuous monitoring of GFRP reinforcement strain.Through the exploration and research of this paper,experimental study of FRP reinforced concrete column provides some reference,to in-depth study the durability of FRP rebar and concrete laid a foundation.