| The conventional emulsified asphalt used in the engineering presents some disadvantages,such as low adhesion strength,not sufficient durability.A newly composite modified emulsified asphalt was prepared by composite agents such as waterborne epoxy resin,polyurethane and acrylate resin.It was tried to apply in fog seal,cold asphalt mixture and asphalt pavement cold recycling.The main contents are as follows:A group of newly composite modified emulsified asphalt were prepared as one or composite additive mixing.Some tests such as fluorescence microscope,curing film,adhesion and pullout test were conducted.It indicated that the composite modified emulsified asphalt has good compatibility,short curing time and strong adhesion.The waterborne epoxy resin and waterborne polyurethane can improve the pulling strength of emulsified asphalt and reduce the temperature sensitivity.But the adhesion properties of modified emulsified asphalt was decreased while the acrylic resin and recycle agent were mixed.The composite modified emulsified asphalt was used in fog seal material.Based on the three factors named as adhesion strength,friction resistance and hardness,the relevant orthogonal test of three levels was carried out.The factors effected the fog seal materials performance was analyzed.The amount of composite modified emulsion and fine sand that sprayed on the pavement surface was recommended.Some tests of the fog seal materials such as adhesion,curing time,friction resistance,water permeability and Cantabro test were conducted.The results show that the performance of the new fog seal material can be enhanced on a certain degree.The suitable mixing proportion range of the composite modified emulsion asphalt used for fog seal material was also recommend.The composite modified emulsified asphalt was also prepared to use in cold asphalt mixture(CAM).The Mashell,Cantabro,fatigue and dynamic stability tests were performed.The results showed the properties of the cold mixture such as the Mashell stability,Cantabro mass loss and compressive strength and dynamic stability can be improved.The strength of CAM was increased with the curing time.Through these relevant experiments,the best water content,the optimum oil-stone ratio,the cement content,and the corresponding mixture ratio of composite modified additive were obtained.The composite modified emulsified asphalt can also be used in asphalt pavement cold recycling.The RAP synthetic gradation by adding new aggregate are determined by extraction test.Among the synthetic gradation,RAP was accounted for 75%.The relevant road performance of the RAP with the composite agents was tested.The results can be showed that with the increase of agent content,the splitting strength,freezethaw splitting strength,anti-raveling properties and high temperature stability are improved more.Based on these experimental results,the optimum water content,the dosage of recycling agent,the oil-stone ratio,and the corresponding mixture ratio of composite modified additive were proposed. |
