Structural Mechanics Analysis Of Continuous Reinforced Concrete Pavement With Basalt Fiber Bars

At present,roads in China’s tropical Marine area are cement concrete pavement and asphalt concrete pavement,but tropical Marine area has strong regional characteristics.High temperature,high humidity,high salt and high ultraviolet light are very serious to the traditional cement concrete pavement structure,especially the steel reinforcement.Basalt fiber reinforced(BFRP)as a new kind of fiber reinforced high performance material,compared with steel,high tensile strength,corrosion resistance,light weight,energy conservation,environmental protection,the advantages of easy construction,and with BFRP bar production process of ascension,its mechanical performance is more and more stable,and have been shown to use in the cement concrete pavement.According to this conclusion,in the ordinary reinforced concrete pavement,replacing the steel bar with the basalt fiber bar can achieve the purpose of reducing the occurrence of pavement disease and prolonging the service life of the pavement,and has a certain application prospect.At present,for the new type of cement concrete pavement with continuous reinforcement of BFRP bars,the design method of reinforcing bars is basically followed,but the mechanical properties of BFRP bars are different from that of reinforcing bars,so the design method of directly using reinforcing bars is not suitable.Therefore,in view of the above problems,in order to facilitate the promotion of the application of BFRP reinforced concrete pavement,this paper studies the mechanical properties of the BFRP reinforced concrete pavement and crack formation law,through the calculation of the reinforcement and BFRP reinforcement force difference,the design of the road surface has a certain reference value.First of all,the finite element model of continuous reinforced concrete with BFRP bars based on linear elasticity,Winkler foundation and plate bottom continuous support is established by using finite element software.The influence of different pavement structure design parameters on the stress and crack load transfer coefficient of concrete slab is analyzed and compared with that of steel bar.Secondly,established considering thrust load stress destruction of BFRP muscle continuous reinforced concrete finite element model of the plate bottom road.the size affect the mechanical state of the right panel.Thirdly,in order to study the dynamic response characteristics of pavement under moving load,the BFRP-CRCP pavement model under constant speed and deceleration moving load was established,and the influencing factors of pavement dynamic response were analyzed one by one.Finally,based on temperature drop and shrinkage,the theoretical calculation model of stress and displacement of continuous reinforced concrete with BFRP bars was established,and the analytical solutions of maximum tensile stress of concrete,maximum tensile stress of bars and crack width of bars were deduced.The corresponding finite element model was established for verification,and then the influence rules of each design parameter on the three indexes were analyzed.Under vehicle load,the elastic modulus of pavement slab,the thickness of base layer,the elastic modulus of base layer,the reaction modulus of foundation,the elastic modulus of BFRP bars,the spacing of BFRP bars,the diameter of BFRP bars and the position of BFRP bars have no obvious influence on the stress state of concrete slab,while the spacing of cracks has significant influence on the mechanical state of pavement slab.In the case of reinforcing bars and BFRP bars,the axial stress of BFRP bars and steel bars is very small,and the reinforcing bars play a more structural role of restraining the deformation of concrete.The stress of the steel bar is about 3-4 times that of the BFRP bar,and the stress of the pavement plate is almost the same,and the change rule with the influence parameters is similar,indicating that it is feasible to replace the steel bar with the BFRP bar.When the bottom of the slab is void,the stress in the long direction of the concrete slab decreases gradually with the increase of the width of the void area,while the stress in the wide direction of the concrete slab increases first and then decreases under the two reinforcement methods.The load stress can be improved by increasing the plate thickness.The crack width of the BFRP reinforced pavement is larger than that of the reinforced pavement,and the crack spacing is smaller than that of the reinforced pavement.The modulus of the BFRP bars has a significant effect on the crack spacing and crack width.Increasing the modulus of the BFRP bars can help to reduce the crack width and control the crack spacing.The larger reinforcement ratio can reduce the crack width and stress of the reinforcement material,but it will reduce the crack spacing.Small diameter and small spacing should be selected as far as possible when the pavement is reinforced,which is conducive to reducing the crack width and giving play to the advantages of the high tensile strength of the reinforcement material.