Experimental Study On The Compressive Performance Of Prefabricated Reinforced Concrete Columns Strengthened With Carbon Fiber Sheets

As the construction industry to upgrade,traditional architectural patterns to the field of concrete cast-in-situ,easy to produce a large amount of waste water,noise and dust,water pollution and dust pollution,from casting to the molding,takes longer,the serious influence the construction speed,prefabricated construction because of high construction speed,quality assured,the advantage of reducing the pollution,the state vigorously promoted.Assembling concrete structures because of the complexity of the environment,with the accumulation of time,will inevitably produce lower strength,damage accumulation and resistance attenuation,therefore,it is necessary to carry out renovation and their methods of research,the traditional method of renovation and construction is difficult,durability and corrosion resistance is poorer,post-processing is relatively cumbersome,Moreover,the stiffness of the reinforced structure changes greatly compared with that before the reinforcement,and it is easy to have an uncertain impact on the structure.The carbon fiber cloth has the advantages of high strength,light weight,easy construction,good durability,fatigue resistance and so on,which is widely used in the reinforcement engineering of the construction industry.In order to study the compression performance of prefabricated concrete columns before and after reinforcement,this paper conducted an experimental study on the compressive performance of 3 ordinary concrete columns,3 prefabricated concrete columns and 4prefabricated concrete columns strengthened with carbon fiber cloth.The main research contents and results are as follows:(1)In order to simplify the construction process,reduce the construction cost,and consider the safety of the construction,this paper designs a new type of precast block,which is used as a template when pouring concrete,and acts as a part of the concrete and the castin-place concrete after curing.The actual manufacturing process of the specimen shows that the prefabricated block has no slurry leakage or cracking phenomenon,which can meet the requirements of engineering application.(2)The compression performance of the prefabricated column was studied,and the failure phenomenon,bearing capacity,displacement and other performance indexes were analyzed during the test.The results show that the prefabricated block has a restrictive effect on the crack development of the prefabricated column.Compared with cast-in-place column before reinforcement,the bearing capacity of assembled column with small eccentric,which is the largest decrease,compression decreases by 4.9%,which shows that the bearing capacity of assembled column is slightly weakened but has little influence.At the peak load,the vertical displacement of the prefabricated axial column decreases by 25.9% compared with the cast-in-place axial column,the vertical displacement of the prefabricated large eccentric column is not much different from that of the cast-in-place large eccentric column,and the vertical displacement of the prefabricated small eccentric column is increased by 25.8%compared with the cast-in-place small eccentric column,indicating that the prefabricated block has little influence on the deformation performance of the prefabricated large eccentric column.(3)The compressive properties of prefabricated columns reinforced with carbon fiber cloth were studied,and the failure,bearing capacity,displacement and other performance indexes were analyzed.The results show that the bearing capacity and deformation capacity of the assembly column are improved after the reinforcement of CFRP.The bearing capacity of prefabricated large eccentric columns with strip and full package reinforcement increases by 6.4% and 12.3%,respectively,and that of prefabricated small eccentric columns increases by 8.4% and 13.6%,respectively,indicating that after reinforcement,the bearing capacity of prefabricated large eccentric columns increases little,while that of small eccentric columns increases greatly.(4)Considering the strength and eccentricity of precast blocks and the reinforcement method of carbon fiber cloth,a calculation method for the bearing capacity of prefabricated reinforced concrete columns constrained by CFRP is proposed.The results show that the error between the calculated value and the test value is small,and it is safe,which can be used for reference in actual construction.