Research On The Performance Of High Modulus Asphalt Mixture Based On No. 15 Hard Asphalt

Refering to the design concept and method of French High Modulus Asphalt mixture(EME2),two types of 15#hard asphalt of China and France were adopted and the EME-14continuous type,EME-14 intermittent type and HMAC-20 type commonly used in the middle and lower layers Asphalt were selected to study the road performance,mechanical properties and fatigue life of different types of low-mark High Modulus Asphalt mixtures by using the performance test of French asphalt mixture design level 1 to level 4.Based on the above experimental research,whether the domestic 15#hard asphalt mixture meet the performance index requirements of French High Modulus Asphalt mixture was evalusted,and the range of dynamic modulus suitable for Chinese modulus parameter conditions(20°C、10Hz)was put forward.The main research results obtained are as follows:Through the conventional asphalt performance test and asphalt rheological rebound test,the physical and mechanical indexes of 15#asphalt of China and France,such as penetration degree,softening point,60°C dynamic viscosity,residual penetration ratio and the maximum creep under different stress conditions were conducted in the comparative study to evaluate the performance difference of the two types of hard asphalt.The results show that the performance indexes of both types of hard asphalt meet the requirements of the national standard.French15#hard asphalt has better high-temperature stability and less sensitivity to changes in strain level,while domestic 15#hard asphalt has anti-aging properties.Performance and viscoelastic performance are better.The road performance of the asphalt mixture was evaluated and analyzed through the French Wheel Tracking,low-temperature bending test,and Duriez test.The results showed that the high-temperature performance,low-temperature performance and water stability of the mixtures met the requirements of the standard performance,but different types of low-grade High Modulus Asphalt mixtures showed different road performance.EME-14 intermittent type+domestic15#asphalt mixture explayed the smallest rut deformation rate and the best high temperature stability.HMAC-20+France 15#asphalt mixture showed the best low temperature performance.different types The compressive strength ratio of French 15#and domestic 15#hard asphalt mixtures was close to 1,which indicated the similar water stability for the two kinds of mixture.Through the trapezoid beam complex Modulus test,the modulus evaluation of various types of low-mark high-modulus asphalt mixtures was carried out,and the main curve of the modulus and the phase angle were established to analyze effect of grading type and asphalt material on mixture modulus and phase angle.The complex modulus value(15°C,10Hz)of the two types of hard asphalt mixture(15°C,10Hz)was greater than 14000MPa,both met the evaluation requirements of the modulus of the French high modulus asphalt mixture.The phase angles of mixtures of the same asphalt and different gradation types were similar in value,and the curves were close to coincide,indicating that the gradation type has little effect on the viscoelastic properties of the mixture.The mixture of the same gradation and different asphalt materials can keep the French 15#hard asphalt under high temperature Good elastic properties,low temperature sensitivity,and better performance of the corresponding mixture.Through the two-point bending fatigue test of the trapezoidal beam,the fatigue equation is established.Combining the fatigue equation parameters a and b,the fatigue performance of the mixture and the sensitivity to the change of the strain level are analyzed to study the effect of strain level,gradation type and asphalt material on the fatigue life of low-grade high-modulus asphalt mixture.The fatigue life of the mixture(10°C,25Hz,130με)was more than 10~6 times,which meets the requirements of the legal standard.The fatigue resistance of mixtures of the same asphalt and different gradation types was shown as EME-14 continuous type>EME-14intermittent type>HMAC-20 type,and the sensitivity of the mixture to the change of the strain level is shown as HMAC-20 type<EME-14 intermittent type<EME-14 continuous type.For mixtures of the same gradation type and different asphalt materials,the mixture of domestic No.15 hard asphalt showed better fatigue resistance,but also had more sensitivity to changes in strain level.By comparing and analyzing the dynamic modulus and complex modulus of HMAC-20+domestic 15#asphalt mixture,the conversion model between the two was established,that is y=1.6811x-7993.8,R2=0.9911.On the premise of meeting the modulus requirements of French high modulus asphalt mixture design level 3,It is recommended that the dynamic modulus of the mixture(20°C,10Hz)be at least 15000MPa.Through the research in this paper,It provides a certain reference for the application of domestic 15#hard asphalt mixture in road engineering and the use of domestic dynamic modulus parameter conditions to evaluate the modulus index of High Modulus Asphalt mixture.