| Formula design in the laboratory of epoxy asphalt materials which mainly used in long life and heavy traffic pavement was mainly focused in this paper,and the compatible property and phase structure control methd of the epoxy asphalt materials,the effects of different curing agent on the curing kinetics,the aging mechanism under simulated natural conditions,and the prospect of the epoxy asphalt materials were also study in details.The resuts showed that:1)The study on the compatible property and phase structure control of the epoxy asphalt materials:In this section,a serious of active epoxy-asphalt compatibilizers were prepared by low molecular weight epoxy resin and ton oil,and tetrabutyl ammonium bromide and stannous chloride which used as the phase transfer catalyst,a compatibilizer was prepared by the reaction of tung oil and epoxy resin.In this study,the active compatibilizer could not only dispersed asphalt to submicron or nanoscale,but also could greatly enhance the compatibility of epoxy and asphalt,and the mechanical properties would also greatly increased,at the same time,the active compatibilizer could effectively prevent the formation of cellular damage in asphalt.The results showed that:if the curing reaction of epoxy resin didn't occur,the compatibilizer could only play as the plasticizing agent of asphalt;but if adding amount of sebacic acid as curing agent in epoxy-asphalt material systems,the sebacic acid could also increase the compatibility of epoxy resin and asphalt,with increasing of sebacic acid content in epoxy-asphalt material systems,the dispersed particle size of asphalt in epoxy resin could become smaller.When the sebacic acid content was above 11phr,the dispersed particle size of asphalt could reach at the range of 5?10?m.Furthermore,while when Methyl-tetrahydrophthalic anhydride(MeTHPA)or Tung oil anhydride(TOA)were added into sebacic acid,the shter molecular chain and fairly higher rigidity of them enable the curing with epoxy resin generate network structures with small cross-linking girds and high rigidity,in which one part of the asphalt was free outside the grid structures formed from the curing of epoxy resin,the other part was enclosed in smaller grid structures,and its movement could greatly restricted.2)The effects of different curing agent on the curing kinetics of epoxy asphalt:In this section,to predict the curing behavior theoretically,the differential scanning calorimetry(DSC)method was used to investigate the curing process of epoxy-asphalts which were prepared by sebacic acid,methyl-tetrahydrophthalic anhydride(MeTHPA)and tung oil anhydride(TOA)as curing agents.The apparent activation energy Ea,the pre-exponential factor A,the cure reaction order n,the treating temperature(Ti),curing temperature(Tp)and the proper gelling temperature(TO),were calculated by Kissinger,Crane equations and extrapolating T-?method.The results showed that:the Ea of sample I(using sebacic acid only as curing agent),sample ?(using sebacic acid + MeTHPA as compounding curing agent),sample ?(using sebacic acid + MeTHPA + TOA as compounding curing agent)were 81.29kJ/mol,67.61kJ/mol and 70.41kJ/mol,the A were 32.87×104,1.30×104 and 3.57×104,the n were 0.91,1.00 and 0.89,the T0 wre 392.09K,382.46K and 399.83K,the Tp wre 458.60K,455.36K and 441.55K,the Ti wre 524.38K,520.60K and 519.26K.Comparing the three samples,it could be found that the sample ? was more suitable for practical engineering applications.3)Study on the Aging Mechanism of Epoxy-Asphalt under Simulated Natural Conditions:In this section,based on the freezing thawing cycle test method,mechanical properties test,pH value test,water absorption test,DMA analysis were used to investigate the damage mechanism of epoxy asphalt.The mechanical properties,DSC analysis,FOM analysis and SEM analysis were used to study the aging-damage mechanism of epoxy asphalt under simulated natural conditions,such as light,heat,oxygen and water.These tests were used to provide a theoretical basis for the further application and prevention of breakage of epoxy asphalt materials.The results showed that:with the increasing of freeze-thaw cycle times,the tensile strength,tensile bending strength,marshall stability,tensile bending strength,bending stiffness modulus and the maximum tensile strain of epoxy asphalt decreased.The damage mechanism of epoxy asphalt under the freezing thawing cycle conditions was that:Under dynamic load of vehicles,water through the void of the asphalt concrete,and reach the interface between the epoxy asphalt and aggregate,and finally,lead stripping between the epoxy asphalt and aggregate.The epoxy asphalt materials could be also decomposes.These reasons could cause the crosslinking structure damage of epoxy asphalt.The mechanical properties,DSC analysis,FOM analysis and SEM analysis were used to study the aging-damage mechanism of epoxy asphalt under simulated natural conditions,such as light,heat,oxygen and water.The results showed that:the ductility values of asphalt decreased because of the broken of alkyl side chains and the oxidation reaction of aromatic hydrocarbon and colloid in the asphalt molecular,the curing degree of epoxy resin was slightly decreased at the same time,the dispersion of asphalt in the epoxy resin became uneven,severe cracking and penetrating holes were appeared on the surface of the test specimen because of the repeated UV irradiation and rain water spray.4)Prospect of epoxy asphalt materials:Nowadays,the paving method of the common asphalt pavement material is heating paving technology.This technology approach needs us to heating the asphalt to above 170?(the modified asphalt or rubber modified asphalt is more higher),and heating the stone to 200?,mixing in special mixing plant.There are strict requirements on asphalt materials,such as the transport distance,the paving climatic conditions,and the paving technology.And on the other hand,during the production process of common asphalt materials,the asphalt smoke and other harmful gases because of the high temperature emission could damage the health of construction workers,and even pollute the environment.As a kind of low-carbon-consumption,environmental-protection pavement material,the temperature during production process and application process of cold-mix epoxy asphalt material can not at high temperature(150?180?,but only at room temperature(23?),so,the cold-mix epoxy asphalt material will change the application status of road pavement materials in our country,and even in the global,and also could become a realization of road pavement materials. |
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