Development Of Low-temperature Improved Epoxy Asphalt For Steel Bridge Deck Pavement And Study On Mixture Performance

Epoxy asphalt is mainly made of matrix asphalt,epoxy resin,and curing agent.It has excellent mechanical properties,good high-temperature stability,super fatigue resistance,and durability,and is widely used in steel bridge deck pavement.At low-temperature,the epoxy asphalt mixture is easy to form large temperature stress and cause pavement cracking,which limits its application scope and construction technology.Therefore,it is of great significance to develop epoxy asphalt materials with good low-temperature performance.In this paper,polyurethane modified epoxy resin(U),dimer acid modified epoxy resin(D),and silicone rubber-modified epoxy resin(S)were used to prepare modified epoxy asphalt with laboratory self-made curing agent and compared with E51 epoxy asphalt(EA)which was the mainstream product in the market.The asphalt performance and asphalt mixture performance were studied respectively.(1)According to the technical requirements of epoxy modified asphalt specification,the composition and proportion of epoxy modified asphalt were designed.The polyurethane modified epoxy resin(U),dimer acid modified epoxy resin(D),and curing agent(P)were selected through compatibility,viscosity change,retention time,micromorphology,thermal stability,and rheological properties.The preparation process and optimum mix proportion were studied.The optimum mix proportion of low temperature improved epoxy asphalt was determined as the curing agent(P):U:base asphalt=4.4:40:60;curing agent(P):D:base asphalt=1.9:40:60;the best curing temperature was 120℃ and the best curing time was 4h.(2)The thermal stability,low-temperature performance,and rheological properties of polyurethane epoxy modified asphalt(UA)and dimer acid epoxy modified asphalt(DA)were studied under the optimum composition and test conditions,and compared with E51 epoxy modified asphalt(EA).The results showed that the thermal stability of EA was worse than UA and DA.Secondly,the low-temperature performance of DA was the best,and the lowtemperature performance of EA was far worse than UA and DA,but the high-temperature performance of EA was better than UA and DA.The frequency dependence of EA was lower than UA and DA,and the fatigue resistance of EA was better than UA and DA.(3)Based on the Marshall design method,the adhesion,high and low-temperature performance,and water damage resistance of polyurethane epoxy modified asphalt mixture(UAM)and dimer acid epoxy modified asphalt mixture(DAM)were studied,and compared with E51 epoxy modified asphalt mixture(EAM).The results showed that under the optimum asphalt content,the three epoxy modified asphalts had excellent spalling resistance,and the water damage resistance of UAM and DAM was improved compared with EAM.Compared with EAM,the high-temperature stability of UAM and DAM was lower than EAM,but the flexibility of UAM and DAM was improved greatly,and the low-temperature performance was better than EAM.