| The aging phenomenon of asphalt pavement will lead to its low performance,which requires the restoration of the performance of the old asphalt mixture.At the same time,considering the increasing traffic demand in some roads,performance of existing pavements can not meet the demand now.Therefore,the performance of the asphalt after regeneration should be further strengthened.Epoxy asphalt material is used as modifier in the work to study enhanced thermal regeneration.Firstly,the performance of aged asphalt is tested and evaluated using three indicators.RTFO is used to simulate aging under natural conditions,which helps to build the relationship between asphalt aging in nature and laboratory.Suitable regenerant is used to restore the performance of aged asphalt,the influence on performance caused by different regenerant concentration is analyzed to find out the optimum dose of the regenerant.The results show that during the aging process,the penetration and ductility of asphalt decrease,but the softening point increases.The performance of aged asphalt is basically the same as new asphalt when the content of regenerant is set as 7%.Secondly,a kind of epoxy modifier is prepared based on the study of various epoxy modifiers with different proportions.Three indicators of asphalt are controlled during the study of the development of aged asphalt under different curing time and content of the modifier.Marshall Test is conducted to find out the best mixing amount of the modifier.The results show that the best proportion of agent A and B is 0.8:1 and for epoxy resin and curing agent is 1.4:1.After curing for 4 days,the curing reaction of epoxy modifier has been preliminarily completed,which can form a strong strength.After curing for 6 days,the curing reaction is almost completely completed,and the strength is no longer increasing basically.When the dosage of modifier reaches 20%,the stability of asphalt mixture basically meets the requirements.Finally,based on the best mixing amount of the modifier,the modifier and the regenerant are added into aged asphalt to study the variation of three indicators.The changes of asphalt mixture performance(high temperature stability,low temperature crack resistance,water stability)are studied after adding the modifier and regenerative agent,as a result,the disciplinarian of chemical reactions between the modifier and the regenerant is revealed.Meanwhile,the factors which affects the performance of asphalt mixtures are studied.The results show that the reaction between epoxy resin and curing agent is almost done after curing for 6 days.The addition of modifier can help enhance the high temperature stability,low temperature cracking resistance and water stability of regenerated asphalt mixture.When the dosage of modifier is fixed to 20%,the increase of the amount of regenerator will make the high temperature stability and water stability of the asphalt mixture become worse,but its performance is still far more than the performance of regenerated asphalt mixture with regenerator only.Curing time and the content of modifier have a much greater effect on the performance of asphalt mixture compared with that of the content of regenerator. |
PDF Full Text Request