Study On The Road Performance Of PVA Fiber Reinforced Cement Stabilized Bricks And Concrete Recycled Aggregates

In recent years,with the increasing amount of sand and gravel mining in China,resulting in the tension of natural resources and environmental pollution;at the same time,the rapid urbanization,a large number of old buildings demolished,resulting in the construction waste piled up and buried at will,not effectively used,causing irreversible harm to the environment.Therefore,the rational use of construction waste to achieve sustainable development has become a hot topic.In this paper,the road performance of PVA fiber reinforced cement stabilized bricks and concrete recycled aggregates was investigated by indoor tests and finite element simulations.The basic physical properties of recycled concrete aggregate and recycled brick aggregate with particle sizes ranging from 4.75 mm to 26.5 mm were tested;a four-factor,four-level orthogonal test was designed to investigate the mechanical properties,determine the influence of each factor on the recycled aggregate and the optimal ratio,and establish a prediction model based on the test results;a structural model of asphalt pavement with PVA fiber brick and concrete recycled aggregate subbase was established through finite element simulation.The structural model was established by finite element simulation,and the road surface bending and subgrade tensile stresses were analyzed under different subgrade stiffness and different traffic speeds to verify the feasibility of PVA fiber reinforced cement stabilized brick and concrete recycled aggregate as road subgrade.The main findings of this paper are as follows:(1)Through the basic physical property tests of recycled concrete aggregate and recycled brick aggregate,it is found that the recycled aggregate has poor particle shape and more pores and cracks,which leads to a large difference in apparent density,water absorption rate and crushing value between them and natural aggregates.(2)The mechanical properties of PVA fiber reinforced cement stabilized brick and concrete recycled aggregate were investigated by orthogonal tests,and the results showed that: PVA fiber can improve the compressive strength and splitting strength of the material to a certain extent,and the most significant effect on strength enhancement was achieved when the length of PVA fiber was 9mm and the dosing amount was 0.2%～0.3%;the length of PVA fiber had a greater influence on the material tensile to compressive ratio when When the length of PVA fiber is 9mm,the material tensile ratio is the largest and the ductility is the best.(3)According to the results of the orthogonal test,the base ratio was selected and the compressive rebound modulus of PVA fiber reinforced cement stabilized brick and concrete recycled aggregate was tested.The results showed that increasing the cement mixture and brick to concrete ratio could improve the compressive rebound modulus,and the compressive rebound modulus of PVA fiber reinforced cement stabilized brick and concrete recycled aggregate ranged from 800 MPa to 1400 MPa.(4)Taking the pavement structure layer parameters of Jiu Lian Shan Road(Ping An Road to Yi De Road)in Rongjiang New Area,Ganzhou as the benchmark,Abaqus software was used for simulation to reveal the change of maximum road surface bending settlement under different subbase stiffness,and it was found that the change of sub-base stiffness had little effect on the upper layer bottom tensile stress;when the travel speed was 60km/h～120km/h,the faster the speed was,the lower the road surface bending settlement was,and the upper layer bottom tensile stress was.When the speed of traffic is 60km/h～120km/h,the faster the speed of traffic,the smaller the road surface bending,the smaller the tensile stress of the upper layer.