| China is a big historical and cultural country,and many ancient buildings and landmark buildings are symbols of China’s cultural deposits.With the passage of time,the safety and use requirements of these cultural buildings have been unable to meet the social requirements.As the symbol of Chinese culture,ancient buildings cannot be dismantled together.At this time,structural reinforcement is needed to repair and transform the buildings.China is a country with many natural disasters.Natural disasters not only bring loss to people’s life and property safety,but also cause damage to buildings.To minimize economic losses,for some buildings with little damage,maintenance and reinforcement measures should be taken to maintain the use.In addition,from 2019,the country will reduce the demolition of old houses.For some buildings are more than 20 years old,the country will adopt the old way of renovation,reinforcement and rectification here is particularly important.In fact,the implementation of reinforcement technology as early as the 1980 s has begun,the current reinforcement technology has been very mature,for the new reinforcement material research is more in-depth.Basalt Fiber Reinforced Polymer(BFRP)reinforcement is the subject of this paper.Basalt fiber is a sort of new material,not only has all the high strength of carbon fiber,and good anti-corrosion of glass fiber,non-magnetic and many other advantages,and basalt fiber is natural rock as raw material,is a pure natural inorganic material,rich in raw materials with independent intellectual property rights,low cost.In order to have a deeper understanding of the bonding property and freezing resistance of BFRP-concrete interface,in this paper,through the finite element simulation study on the bonding properties of BFRP-concrete interface under two conditions of freeze-thaw cycle and freeze-thaw cycle,some relevant conclusions are summarized.1.In the absence of freeze-thaw cycle:(1)In this paper,the cohesion element with thickness is used to replace the adhesive layer for finite element simulation of the bond performance of BFRP-concrete interface.Influence of concrete strength,Thickness of adhesive layer,the bond length and the bond width on the bond strength of the interface is studied by using the method of control variables.(2)The approximate range of softening load was obtained through the variation law of strain distribution curve of BFRP;Based on the strain distribution law of BFRP,the effective bond length and other relevant conclusions are obtained.(3)The influence of concrete strength and adhesive layer thickness on interface ductility was obtained through load slip curve.2.Under the condition of freeze-thaw cycle:(1)In this paper,the freeze-thaw damage model of concrete units was adopted to simulate the frost heave force to study the interfacial bonding properties of BFRP-concrete units under freeze-thaw cycles.Control variables are also used to study the influence of concrete strength and other factors on the interfacial bonding properties under freeze-thaw cycles.(2)According to the distribution law of load slip curve under different freeze-thaw cycles,the influence of different freeze-thaw cycles on interface stiffness and ductility was summarized.(3)Through the distribution law of the stress distribution curve under freeze-thaw cycles,the effects of freeze-thaw cycles on ultimate bearing capacity,ultimate strain and interfacial ductility are obtained;The influences of the number of freeze-thaw cycles on the softening load and the effective bond length were obtained.(4)According to the bond slip curve under freeze-thaw cycles,it is concluded that freeze-thaw cycles will reduce the interface fracture energy. |
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