Experimental Study On Mechanical Properties Of Steel Fiber And Macro Polypropylene Fiber Reinforced Recycled Concrete

With the rapid development of the global construction industry,a large number of waste concrete is produced after discarded concrete buildings be demolished?a large number of discarded concrete buildings to be demolished.The recycled concrete technology has become a hot issue in academia and engineering.Fiber modified concrete has been extended from original concrete to recycled concrete after fiber concrete technology has been matured.Furthermore,a number of new artificial fibers have also been applied to fiber modified concrete,The study on the basic mechanical properties is a promotion for its early application to engineering practice.This paper is based on recycle aggregate concrete(RAC),adding steel fiber,macro polypropylene fiber and hybrid fiber to RAC,with two dominate parameters both replacement rate of recycled coarse aggregate(30%,60%)and the volume rate of steel fiber(0.5%,1.0%,1.5%),macro polypropylene fiber(0.7%,0.9%,1.1%)as variable,to study the mechanical properties of modified concrete by comparative text in two types of modified RAC.Making a total of 25 groups 150,150mm X 150mm X 150mm cubes of cube compressive strength and splitting tensile tests and text were carried out,making a total of 25 groups75 ?150mmX300mm cylinders for axial compressive test and the text were carried out,and also making a total 43 groups 129 150mmX 150mm X 550mm beams for bending test.In this paper,the main research content includes the following five parts;Firstly,the mix ratio of RAC was determined.Adding additional water was determined as the process of mixing RAC,and using it to adjust the amount of mixing water.The performance of new mix-concrete was tested.Secondly,the cube compressive performance of two types modified RAC was researched.The effects of recycled coarse aggregate with different replacement rate and different dosage of steel fiber or Macro polypropylene fiber were investigated on the basic mechanical properties and failure characteristics.The contract of two types modified RAC's compressive performance were analyzed.Thirdly,the cube splitting tensile performance of two types modified RAC was researched.The effects of recycled coarse aggregate with different replacement rate and different dosage of steel fiber or Macro polypropylene fiber were investigated on the basic mechanical properties and failure characteristics.The contract of two types modified RAC's splitting tensile performance were analyzed.Fourthly,the beam bending performance of two types modified RAC was researched and the load-deflection curve of two types modified RAC were obtained.The failure energy of two types modified RAC was calculated.The effects of recycled coarse aggregate with different replacement rate,different dosage of steel fiber or Macro polypropylene fiber and the section form were investigated on the basic mechanical properties,failure characteristics and failure energy.Fifthly,the cylinder axial compressive performance of two types modified RAC was researched and the stress-strain curve of two types modified RAC were obtained.The effects of recycled coarse aggregate with different replacement rate and different dosage of steel fiber or Macro polypropylene fiber were investigated on the basic mechanical properties and failure characteristics.