Preparation And Properties Of Epoxy Asphalt Toughened By Modified Polyethylene

Epoxy asphalt pavement bridge deck was first applied in China’s Nanjing Yangtze River Second Bridge and showed good road performance,and rapid development,especially in the large-span bridge decks that are widely used.Although epoxy asphalt(EA)has high strength and good water resistance,thermal stability,solvent resistance,and durability,EA in the construction of viscosity growth is too fast,allowing the operation of the short retention time and other problems,is not conducive to construction;coupled with the epoxy resin and asphalt due to differences in density and polarity make it poorly compatible,after curing becomes hard and brittle,so that in the actual application process due to temperature changes in the external environment and load and other effects,and cracking and other defects,thus affecting the performance of epoxy asphalt road.Therefore,the study of the compatibility and toughness of epoxy asphalt has important application value and significance.Firstly,two curing agents were selected to prepare EA,and the best ratio of the compound curing agent was determined by the comparative study of mechanical properties,and the effects of different curing temperatures and maintenance times on the mechanical properties of EA were studied.The morphological changes of EA under different curing times were observed by fluorescence microscopy,and the changes of epoxy groups were observed by Fourier transform infrared spectroscopy to analyze the curing process of epoxy asphalt.Meanwhile,a new reactive epoxy asphalt modifier-functionalized polyethylene,which can form a pre-crosslinked network,is introduced.The long aliphatic chain at one end of the molecule is non-polar and compatible with asphalt;the epoxy group(PE-t-E)and an amino group(PE-t-N)at the other end are polar and compatible with epoxy resin,both of which can significantly improve the storage stability as well as toughness of EA.Compared with common bulking agents,the new modifier forms a stronger chemical bond between asphalt and epoxy resin molecules through cross-linking reaction,which fundamentally improves the compatibility of asphalt and epoxy resin.Second,to further reduce the cost of polyethylene modified EA and to maximize its compatibility and toughness,commercial modified polyethylene(low-density polyethylene grafted glycidyl methacrylate(PE-GMA)and low-density polyethylene grafted maleic anhydride(PE-MAH))was introduced to modify EA,and the compatibility of PE-GMA and PE-MAH modified EA was investigated by fluorescence microscopy and scanning electron microscopy,and the effects of PE-GMA and PE-MAH on the low-temperature toughness of EA were explored by mechanical properties and dynamic mechanical analysis.It was found that the introduction of PE-GMA and PE-MAH improved the compatibility of asphalt and epoxy resin,so the dispersion coefficient(PDI)of its modified EA is 1.1～1.4 much lower than that of pure EA;Although the EA viscosity is increased,the viscosities of PE-GMA and PE-MAH modified EA at 120 min are about 1500 m Pa·s and 2000 m Pa·s,respectively,with long operation time and suitable compaction viscosity;it can also effectively increase the EA low temperature toughness and has high damping performance and tanδ value,thus improving the EA pavement durability and comfort.