Study On The Durability Of Warm Mix Asphalt Mixture In Tunnel

While ensuring that the pavement performance meets the requirements,warm mix asphalt solves the serious pollution problem of traditional hot mix asphalt.Adopting warm mixing technology,the production temperature of asphalt mixture can be reduced by more than 30℃,the emission of harmful gases will be greatly reduced,and the construction environment will be significantly improved.Therefore,the study of warm mixing technology is of great significance to the development of asphalt pavement in tunnels.At home and abroad,there are many studies on the influence of different warm mixing agents on the mechanical properties and road performance of asphalt mixture,but there are few studies on the long-term performance of warm mixing asphalt mixture,and there is a lack of comparison of different types of warm mixing technologies.In this paper,the compaction characteristics,high temperature rutting,low temperature cracking,water damage,fatigue damage,aging,which have significant influence on the durability of asphalt mixture,are studied to provide reference for the application of warm mixing technology.In this paper,Sasobit,Aspha-min and DWMA-1,three kinds of warm mixing agents with different cooling mechanisms,were selected to analyze the physical properties,viscosity-temperature properties and rheological properties of warm mixing modified asphalt;Preparation for AC-20 C,warm mix asphalt mixture by Marshall compaction test,change different compaction temperature and the compaction times,measuring the porosity of the specimens and the degree of stability,analysis its change rule,with 4% porosity method to determine the mixture of the best compaction temperature,the void fraction is established with the power function relation between the number of compaction,the compaction difficulty coefficient is defined and based on rotating compaction compaction curve and the compaction work parameters of the analysis of the construction of warm mix asphalt mixture workability and deformation resistance;The long-term aging of the mixture was simulated by laboratory test,the high and low temperature performance and water stability of the mixture before and after aging were studied,and the performance attenuation law of the warm mixed asphalt mixture before and after aging was put forward;The fatigue cracking resistance and crack propagation of warm mixed asphalt mixture were studied by splitting fatigue test,direct tensile fatigue test and crack propagation test of semi-cylinder;The energy saving and emission reduction effects of different temperature mixture are analyzed by theoretical calculation,and some reasonable Suggestions are put forward for the construction of asphalt pavement.The results show that Sasobit and Aspha-min can improve the high-temperature rheological properties of asphalt and have a good viscosity reduction effect,DWMA-1has a little influence on the asphalt performance indicators;Air voids of asphalt mixture with the increase of compaction temperature linearly decreases,and along with the increase of compaction times is power function decreases,and mechanical strength has a linear decline change with the increase of void fraction,Sasobit,Aspha-min,the DWMA-1 can make mixture compaction temperature 25 ℃,20 ℃ and 15 ℃,the best dosage,3% and 0.3% and 0.6% respectively,and the warm mix asphalt mixture have good construction workability and resistance to deformation ability;Sasobit and Aspha-min improved the high temperature performance of the mixture,but degraded the low temperature performance and water stability of the mixture to varying degrees;DWMA-1 improves the low temperature performance and water stability of the mixture;Sasobit and DWMA-1 warm mix asphalt mixture also has good anti-aging characteristics;Sasobit improves the fatigue life of the mixture,and the specimens are characterized by brittle failure;Aspha-min and DWMA-1 have little impact on the fatigue performance of the mixture,and the specimens are characterized by plastic failure;The energy saving and emission reduction benefit of warm mix asphalt mixture is remarkable and has important economic and social value.