An Experimental Study On Performance Of Fiber Asphalt Mastics And Strength Of Fiber Reinforced Asphalt Mixtures

Along with the rapid economic development in our country, the modern highway transportation characterized with high traffic density, high load and channelized traffic, the asphalt pavement damage is more serious. Researchers in highway engineering used to improve asphalt mixture's graduation and quality of asphalt binder to raise the performance of asphalt pavement. The method of using some fiber to reinforce asphalt mixture becomes popular. It is expectative because fiber can improve pavement performance based on its high tensile strength and high modulus.This thesis uses Superpave to evaluate the effect of plant fiber and glass fiber content on rutting resistence and fatigue crack resistence of asphalt mastic. Based on the study of rutting resistence and fatigue crack resistence performance of orginal, short-term aging and long-term aging asphalt mastic, combineing with the theory of composite material and visco-elastic mechanics, it is obtained that glass fiber and plant fiber reinforce asphalt mastic to improve performance of asphalt pavement. Glass fiber mainly reinforces asphalt mastic and plant fiber steadies asphalt mastic.The results indicate that increasing dust-to-binder ratio can improve rutting resistence but decrease fatigue crack resistence of asphalt mastic. It is suitable that dust-to-binder ratio is less than 1.2; It is obtained that increment of the fiber content can improve rutting resistence and fatigue crack resistence of asphalt mastic when dust-to-binder ratio is 0.9. Optimal fiber content for best fatigue crack resistence of asphalt mastic is 6%; High temperature rutting resistence decreases and intermediate temperature fatigue crack resistence increase as temperature increases; High temperature rutting resistence increases and intermediate temperature fatigue crack resistence decreases as angular frequency becomes bigger. The results of AC-20 asphalt mixture's test indicate that fiber can increase Marshall stability and indirect tensile strength. The improvement of 6% plant fiber content to asphalt mixture's indirect tensile strength is 3.4% but 6% glass fiber content is 7.8% in optimum asphalt content while 6% plant fiber content to asphalt mixture's indirect tensile strength is 5.4% but 6% glass fiber content is 15% in average asphalt content.