Investigations On Hot In-place Recycling Technology&Temperature And Aging Testing For Asphalt Pavement

Hot In-place Recycling is a new technology, which can repair pavement in a series ofprocesses: heat in-place, scarifying, mixing. It has been extensively applicated in domesticpavement maintenance projects recently. This technology is efficient, economical,environmental friendly and has signifcicant economic and social benefits. Additionally itaccords with our country’s sustainable development strategy.Combined the theory of asphalt ageing and experiments with some reconstructionengineerings, this paper analysis the characteristics of asphalt and asphalt concrete, includingageing and rejuvenating discipline. And meanwhile, a shearing strength experiment is made toexplore the regular pattern of the shearing strength between pavement layers.Intermittent heating on the site was adopted to investigate thermal ageing properties ofold asphalt in the experiment that can get better evaluation of thermal ageing level in the HotIn-place Recycling construction progress. In order to compaired with the shearing strength ofthe traditional technology, the shearing strength of core samples, got from the pavementwhich is repaired by the way of resurfing and remixing, was tested through the experiment.Asphalt penetration, softening point, ductility are important indicators of asphaltperformance. The ageing and rejuvenating discipline of asphalt are determined in this paperbased on the changes of softening point, penetration, ductility along with aging time and thedosage of regeneration agent. Moreover, the relationship between indoor ageing time andatmospheric ageing time is discussed futher through the way that solving the fitting equationof asphalt performance and indoor ageing time after the values of the three indicators are gotby recycling old asphalt.Different aggregate ratio is bound to affect void ratio, flow value and stability of theasphalt mixture. Therefore, for the asphalt mixture, this paper proposes to study the ageingand rejuvenating discipline of asphalt mixture in the direction of the changes of void ratio,flow value and stability along with ageing time and the dosage of regeneration agent.Based on the results of experiments’ analysis and practical engineering applications, thispaper draw the conclusions:a regular pattern of the asphalt temperature and aging variation;how to decide the optimal mixing amount and the influencing factors of rejuvenating; therelationship between natural aging and laboratory measured values; the contact between voidratio, flow value and stability of the asphalt mixture and aging asphalt; the performent of theasphalt mixture meet the requirements after Hot In-place Recycling; different manners of Hot In-place Recycling have a obvious effect on interlaminar shear strength; the pavement can beuniformly heated in a short period by intermittent infrared heating and so on, which wouldprovide a reference value to the Hot In-place Recycling technology of the existing asphaltpavement.