Effect Of Temperature And Loading Rate On The Mechanical Properties Of Carbon Fiber Asphalt Concrete

Asphalt concrete is widely used as the anti-seepage body of earth-rock dams to ensure the antiseepage performance of the structure due to its great flexibility,strong impermeability,and excellent deformation performance.In recent years,more and more dams with asphalt concrete core walls and higher dam heights have made hydraulic asphalt concrete materials need to be improved to adapt to the continuous improvement of dam construction technology,followed by the safety of earth-rock dams.Sexual issues,including the effect of temperature and loading rate on the properties of asphalt concrete materials.Carbon fiber has the advantages of light weight,high strength,corrosion resistance and high temperature resistance.Not only can it carry loads as part of the structure,but it can also function as a functional material.In this paper,chopped carbon fiber is mixed into asphalt concrete to improve its performance to improve its anti-cracking and impact resistance,inhibit the generation and expansion of cracks,and improve the anti-permeability of asphalt concrete.In this paper,the combination of theoretical analysis and experiment is used to study the influence of temperature and loading rate on the performance of carbon fiber asphalt concrete through shear test and split test(indirect tensile test).The main research conclusions are as follows:(1)Analyzed the crack development during the test and the appearance of the test block after it was destroyed.It was found that the failure form of the test block at low temperature(below 0℃)was brittle failure,the crack development speed was fast,and there was debris during the crack development process.drop,and becomes more pronounced with increasing shear rate.The failure form of the test block at 20℃ and 40℃ is plastic failure,the cracks develop slowly,and the carbon fiber material has an obvious pulling effect at the fracture,which plays a strengthening effect.(2)Compared with ordinary asphalt concrete,the asphalt concrete mixed with carbon fiber has 10%～25%improvement in various performance evaluation parameters in the shear test and splitting test,which shows that after the incorporation of chopped carbon fiber materials,the ability of asphalt concrete to resist oblique shearing and tensile resistance is enhanced,and carbon fiber materials play an important role in increasing the cracking resistance and crack propagation performance of asphalt concrete materials.(3)Analyzing the shear stress-strain curve of carbon fiber asphalt concrete in the whole process,it is found that under the temperature condition of 20℃,the linear phase is longer and the strain in the linear phase is also larger,which can maintain a large The strain is of great significance to the stable operation of the dam.Combining with the theory of fracture mechanics,the crack development process and mechanism of carbon fiber asphalt concrete splitting experiment were analyzed by segmental cracking energy,cracking index and other parameters.Best of all test conditions.Therefore,the ideal working temperature of carbon fiber asphalt concrete is 20℃.At low temperatures(below 0℃)and high temperatures(above 40℃),the work performance of carbon fiber asphalt concrete is poor,and the stress performance is unstable,so it is not suitable for long-term work of carbon fiber asphalt concrete.(4)Combined with the time-temperature equivalent principle to analyze the shear modulus and shear strength of carbon fiber asphalt concrete to obtain the corresponding main curve fitting formula.The basic parameters of the splitting test were analyzed,and the relationship between the splitting tensile strength,splitting failure tensile strain and splitting failure stiffness modulus and temperature and loading rate was obtained by fitting within a certain range of loading rates when the temperature was lower than 0℃ Mode.The fitting data is in good agreement with the experimental data,and the obtained fitting formula can calculate the experimental parameters in a certain temperature range and at the loading rate relatively accurately.