Experimental Study On Bond Behavior Of Recycled Aggregate Concrete And Basalt Fiber Reinforcement

At present,in the case of lack of resources,it is a trend to study renewable resources.Natural aggregate in civil industry is one of them.Therefore,it is necessary to study recycled concrete and reuse the waste concrete resources.Corrosion of steel bars is an important factor affecting the stability of structures.If the problem of corrosion of steel bars is solved,the practicability and durability of structures can be enhanced.Basalt fiber reinforced composite bar(BFRP bar)has good properties,such as corrosion resistance,high tensile strength,etc.It can be used for longitudinal stress bar and prestressing bar of components.Therefore,this paper will study the performance of BFRP bars and recycled concrete.The mechanical properties of recycled concrete will be studied by the replacement rate of recycled aggregate and the strength grade of concrete.The bond performance of BFRP bars and recycled concrete will be studied by the replacement rate of recycled aggregate,the strength grade of concrete and the diameter of BFRP bars.Specific work includes:(1)The basic mechanical properties of recycled concrete(cubic compressive strength,axial compressive strength,splitting tensile strength and elastic modulus)were studied by changing the replacement rate of recycled aggregate(0,25%,50%,75%,100%)and the strength grade of concrete(C40,C50,C60).The test results show that the recycled concrete are similar to those of ordinary concrete,but the higher the strength grade,the better the integrity of the compressive strength.Because the performance of recycled aggregate is unstable,there are many interfaces and cracks in the recycled aggregate,when the replacement rate of recycled aggregate increases,the strength will suddenly increase,while the elastic modulus of recycled concrete will first rise and then decrease.(2)The bond properties between recycled concrete and BFRP bars were studied by central pull-out test,changing strength grade of recycled concrete(C40,C50,C60),replacement rate of recycled coarse aggregate(0%,25%,50%,75%,100%)and diameter of BFRP bars(12mm,14 mm,20mm).The test results show that the bond strength between BFRP bars and recycled concrete increases with the increase of strength grade of recycled concrete,but the bond strength decreases with the increase of replacement ratio of recycled aggregate or diameter of BFRP bars,and the slip value of bond-slip curve decreases with the increase of replacement ratio of recycled aggregate.(3)Through Origin fitting,the constitutive model suitable for the test in this paper is established,and the fitting results have strong correlation,which can provide theoretical reference for the engineering application of BFRP bars recycled concrete.