Experimental Study On Mechanical Properties And Acoustic Emission Characteristics Of Steel Fiber Recycled Concrete

As urbanization accelerates and construction industry prospers in our country,the volume of demand for beton is swelling with each passing day,in the meantime,natural material of construction such as sand and stone are consumed in large quantities,which leads to the increasing shortage of primary source,and a great quantity of construction waste material is imperatively come into being,which has exerted a grievous detrimental effect to nature ambient and people’s exists.Oeder to solve the deficiency of architecture materials and a great deal construction waste material output prominent contradiction,in response to China ’s strategic objectives of efficient recycling of resources and green sustainable development,this thesis uses the reclaimed coarse aggregate derived from demolished concrete beams to replace the crushed pebble coarse aggregate according to the designed proportion and mix it into recycled concrete,so as to achieve the reclaim and utilize discaeded concrete,decreased the waste of construction waste and the use of natural coarse aggregate,which is in line with the planning objectives of the unity of economic,environmental and social effects advocated and implemented by the state.Due to the defects of recycled concrete such as brittleness and poor toughness,its application domain is given widerly restricted,order to resolve such issues,in this thesis,quantum sufficient of steel fiber expansion is added to reclaimed concrete,and takes the Volume fraction of steel fiber,reclaimed coarse aggregate replacement percentage and matrix strength of broken pebble concrete serve as parameters.The basic mechanical behavior,bending resistance and shear resistance and acoustic emission characteristics of steel fiber reinforced recycled concrete are major studied,which supplies a consult application and research of steel fiber reinforced recycled concrete in civil engineering.The main research operations detachment production are as below:(1)The development and research status of recycled concrete,steel fiber reinforced concrete and acoustic emission detection technology are introduced.The physical performance indexes of raw materials for the preparation of steel fiber recycled concrete are tested.(2)The mechanical properties of recycled fiberglass concrete are studied,the effect of various parameters on the compression force,the strength of stress and the axing power of cubes.The calculation models of compression force,the strength of stress and axial power of cubes taking into account Volume fraction of steel fiber and reclaimed coarse aggregate replacement percentage were established respectively.(3)The affects of different parameters on the bending resistance,curved ductibility and load-deflection curve of Volume fraction of steel fiber reinforced recycled concrete was investigated by bending test.(4)The affects of different parameters on the shear resistance,shear ductility and load-deformation curve of Volume fraction of steel fiber reinforced recycled concrete was investigated by shear test.(5)Based on the acoustic emission signals and waveforms collected during the bending and shear tests,the acoustic emission ringing count,energy and AF-RA parameter analysis and acoustic emission damage location map were used to analyze the damage evolution process and fracture mode acoustic emission characteristics of beam specimens and prism specimens with different parameters.