Research And Development Of Polyurethane Epoxy Asphalt Bridge Deck Pavement Material And Its Road Performance

Epoxy asphalt is used for steel bridge deck pavement with high strength,excellent high temperature performance,good adhesion and other excellent properties,and its fatigue resistance is much higher than that of ordinary asphalt.When epoxy resin is used to prepare epoxy asphalt,it can change the thermoplastic properties of asphalt,and the obtained epoxy asphalt is a thermosetting material.Epoxy resin in the mechanical properties of asphalt to enhance,due to the epoxy resin brittle,low flexibility resulting in epoxy asphalt low temperature performance is poor.Therefore,the epoxy asphalt needs to be toughened and modified to improve its low-temperature performance,storage stability,etc.,so as to ensure the road performance of epoxy asphalt pavement.In this paper,polyurethane/epoxy composites were firstly obtained by modifying epoxy resin with self-synthesized polyurethane prepolymer,and the polyurethane/epoxy composites were used for asphalt modification.The optimal amount of polyurethane in the polyurethane/epoxy composite was determined to be 20% by indoor tensile test;and the modification mechanism of polyurethane modified epoxy resin and its cross-linked network structural properties were analyzed by infrared spectroscopy test,and the results showed that the hydroxyl group in the epoxy reacted with the isocyanate group in the polyurethane by chemical grafting;the tensile of the polyurethane/epoxy composite was observed by scanning electron microscope.The tensile section of the polyurethane/epoxy composite was observed by scanning electron microscopy,and the toughening mechanism of the polyurethane modified epoxy resin was further analyzed.The flexible chain segments in polyurethane can effectively absorb energy and prevent further crack expansion,increasing the degree of stress dispersion.Secondly,the viscosity characteristics of polyurethane-epoxy modified asphalt,microscopic phase analysis and mechanical properties tests were conducted to study the construction tolerance time,microscopic phase changes during curing and tensile strength changes of polyurethane-epoxy modified asphalt at different dosing levels;considering the construction tolerance time,compatibility characteristics and mechanical properties the optimum dosing level for polyurethane-epoxy modified asphalt was finally determined to be 40%.The optimum asphalt dosage of 6.7% was determined by Marshall test,and the maintenance condition of the mixture was determined to be 7d at 70°C.The indoor test was conducted on the road performance of the polyurethane-epoxy asphalt mixture such as high temperature stability,low temperature crack resistance and water stability,and the test results showed that the road performance of the polyurethane-epoxy asphalt mixture met the design requirements of the relevant specifications.Finally,the construction process of using polyurethane-epoxy-modified asphalt concrete(EA10)as the underlayment layer of the bridge deck test section and SMA10 as the top layer of the deck pavement was studied.The test section was introduced and the technical characteristics of the raw materials used;the construction process was determined and the completed waterproof binder layer,the polyurethane-epoxy modified asphalt concrete underlayment and SMA10 surface layer were tested,and the test results met the design requirements;finally,the water penetration coefficient and the construction depth of the bridge deck pavement were randomly tested,and the results met the design requirements.