Compressive Behavior Of Nature Jute Fiber Reinforced Polymer(JFRP) Tube Encased Recycled Aggregate Concrete(RAC) With Partially Clay Brick Aggregate(CBA)

With the development of engineering construction in China,increasing group of construction waste is produced,which inevitably contains clay bricks.To solve the problem of preservation of construction waste and realize the resource utilization of construction waste,construction waste has been used to product recycled concrete by many scholars.However,recent research and engineering application show that the strength and ductility of recycled concrete components are both lower than normal concrete components.In addition,the inner structure is more complex and the shrinkage of recycled concrete is larger than the normal concrete components,as well as the creep.Because of the properties of high strength,light weight,corrosion resistance,installation,etc,FRP(Fiber Reinforced Plastic)has been widely used in civil engineering,while traditional artificial fiber,with high cost and low yield,is not green and sustainable.In order to meet the environmental demand and to develop sustainable materials,the low-cost,easily drawing,green and sustainable natural fiber has attracted the attention of many countries and fields.Natural fiber has the advantages of lower density,better tensile performance,no irritation,no damage to the equipment,lower energy consumption,degradation of cocoa,lower price and lighter weight,compared with the synthetic fibers such as carbon fiber and glass fiber,which have provided support and possibility for the development of natural fiber reinforced composite plastics.Thus,extensive studies have been performed on the research and application of natural fibers.In order to promote the processing technology of construction waste and the application of recycled concrete,Recycled concrete is effectively combined with natural fibers in this thesis,because it can not only solve the defects of recycled concrete,but also make full use of the advantages of natural fibers.Thus,the Jute fiber reinforced plastic(JFRP)tube encased recycled aggregate concrete(RAC)with partially clay brick aggregate"(CBA),termed as JFRP-RAC-CBA,and the Jute fiber reinforced plastic(JFRP)tube encased sisal fiber reinforced concrete(SFRC)with partially clay brick aggregate(CBA),termed as JFRP-SFRC-CBA,are mainly studied.And the following work is conducted around this point.(1)Tensile behavior of JFRP composites has been studied.The mechanical properties of JFRP,including tensile strength,ultimate tensile strain and stress-strain curves,etc,are acquired by testing 6-layers JFRP composites with different angles.(2)Compressive tests of the JFRP-RAC-CBA and the JFRP-SFRC-CBA have been con-ducted.A total of 36 cylindrical specimens(i.e.27 confined cylinders and 9 plain concrete cylinders)with 150mm diameter and 300mm height were prepared for the axial compression tests.The following parameters were considered:1)the strength of the core concrete,2)the direction of jute fiber(JFRP),and 3)the number of sisal fiber(SFRP)in concrete.With load increasing,the axial force,axial deformation and hoop strain were measured by force sensors,dis-placement sensors and strain gages,respectively.The JFRP-RAC-CBA and the JFRP-SFRC-CBA showed better performance than unconfined specimens in the test.(3)Compressive strength model and ultimate strain model of JFRP-RAC-CBA have been studied.The comparison of experiment result and existing models are carried out and the modified strength model and ultimate strain model for JFRP-RAC-CBA is proposed,respectively.(4)Compressive strain-stress model of JFRP-RAC-CBA is studied.Existing stress-strain models of FRP confined concrete are studied with the test results.Comparison of the proposed stress-strain model of JFRP-RAC-CBA and the test results is conducted as well.(5)The oretical study of JFRP-SFRC-CBA is conducted.A comparison of JFRP-RAC-CBA and JFRP-SFRC-CBA is carried out.Then modified models of strength,ultimate strain and stress-strain relationship are proposed after analysis.