Performance of epoxy asphalt mixtures toughened with different fibers
[Objective]Epoxy asphalt mixtures are primarily used in pavements of long-span steel bridge decks.The heavy load traffic and orthotropic structural characteristics of steel bridge decks require epoxy asphalt mixtures with high deformation performance,material strength,and fatigue performance.The issues encountered with epoxy asphalt mixtures include ecracking and fatigue damage.Due to the high hardness and strength of epoxy asphalt mixtures,when the steel bridge deck deforms under sea wind loads,the internal stress of the material cannot be fully transmitted.Over time,microcracks can develop within the materialunder heavy traffic and vehicle loads.This results indeclined durability and causes cracks,pits,and other deformations,leading to functional impairment of the pavement layer.Therefore,we propose incorporating fibers to enhance the cooperative deformation capacity and service life of epoxy asphalt mixtures.[Methods]In this paper,the epoxy asphalt mixture was reinforced to satisfy the requirements of anticracking,antifatigue,etc.,and the reinforcing effects of different fibers(basalt fiber,glass fiber,and polyester fiber)on the epoxy asphalt mixture were studied.First,tensile tests were performed on epoxy asphalt to determine its construction temperature and elongation at break.Using the Marshall test,the mixture design of EA-10 epoxy asphalt mixtures with basalt,glass,and polyester fibers and without fiber was conducted to measure the mineral composition and optimal oil-stone ratio of the four EA-10 epoxy asphalt mixtures.The research findings revealed that the retention time and tensile strength of epoxy asphalt satisfy the engineering requirements,and the optimal oil-stone ratios of the epoxy asphalt mixture without fiber and with basalt,glass,and polyester fibers are 6.5％,6.7％,6.6％,and 6.8％,respectively.Second,the road performance of the four EA-10 epoxy asphalt mixtures was examined by rutting,low-temperature small beam,immersed Marshall,and freeze-thaw splitting tests.Compared with the mixture without fibers,the fibers improved high-temperature rutting and low-temperature crack resistance,and their water stability performance was also improved to a certain extent.This shows that the fibers can improve the road performance of the mixture and that the basalt fiber has the best improvement effect.Finally,the toughening effects of the four EA-10 epoxy asphalt mixtures were exploredby impact testing.[Results]The results indicated that the impact toughness at-10 ℃ is significantly lower than that at 15 ℃.At the same time,doping fibers can improve the impact toughness of the mixture,with the impact toughness of basalt fiber being optimal.① The hot-mixed epoxy asphalt was subjected to viscosity tests at different temperatures(140,150,160,170,180 ℃)and elongation at break tests,which showed that the construction temperature of epoxy asphalt mixtures is optimal for construction temperatures of 160-170 ℃,and the construction retention time was approximately 2 h.② The results of the low-temperature beam bending test to study the anticracking performance of the four EA-10 epoxy asphalt mixtures showed that fiber doping can significantly enhance the anticracking performance of epoxy asphalt mixtures,and basalt fiber-doped mixtures displayed the best anticracking effect.③ The impact test demonstrated that the impact toughness of the fiber epoxy asphalt mixture at 15 ℃ is better than at-10 ℃.[Conclusions]This paper provides a scientific basis for guiding the application of fibers in epoxy asphalt mixtures and a reference for researching fiber toughening technologies of epoxy asphalt mixtures.
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