Effect Of De-icing Additives On Aging Properties Of Bitumen And Its Mixture

In winter,the snow and ice on the asphalt pavement surface not only greatly reduce the efficiency of road transport,but also easily lead to traffic accidents.How to remove the ice and snow,reduce the occurrence of traffic accidents in a timely manner,so as to ensure the smooth flow of the transport has been the problem that need to be solve all around the world.Since the self-ice-melting asphalt pavement technology can effectively solve the problem of road ice and snow in winter,it has gained more and more attention.The so-called self-ice-melting asphalt pavement technology is with de-icing additives added in asphalt mixture,with the paving of the road by compression,vibration,abrasion and so on,de-icing additives slowly precipitate to the road surface to lower the freezing point of snow and ice,so as to realize automatically the control and limitation of ice and snow on pavements.However,the addition of de-icing additives will not only effect the road performance of asphalt mixture,but also the aged bitumen and asphalt mixture affect the long term de-icing effect of self-ice-melting asphalt pavement.Therefore,research on the influence of de-icing additives on the aging performance of bitumen and asphalt mixture has an important guiding role for the selection of the de-icing additives and the development and application of self-ice-melting asphalt pavement technology.This paper choosed NaCl,wrapped NaCl(B-NaCl)and chloride ion intercalated Mg-Al layered double hydroxides(LDHs)de-icing additives and de-icing additives/asphalt mortar were prepared,the effect of three de-icing additives on thermo-oxidative and ultraviolet aging properties of bitumen were investigated by thin film oven test(TFOT),pressure aging vessel(PAV)and ultraviolet(UV)radiation test;the self-icing-melting asphalt mixture was prepared with the replacing of mineral powder by de-icing additives,and the effect of three de-icing additives on aging performance of the bitumen and asphalt mixture were investigated by the shortterm hot oxygen aging test,and long-term thermal oxidative aging test and long-term light oxidative aging wear rain test of asphalt mixture;and finally effects of aging and wear rain on long-term ice melting performance of asphalt mixture prepared with different de-icing additives were also studied.The main conclusions are as follows:(1)There is a big difference between the effect of the three kinds of de-icing additives on the short-term and long-term thermal oxidative aging and ultraviolet aging property of bitumen.LDHs can significantly improve the short-term and longterm thermal oxidative ageing and ultraviolet aging property of bitumen,while NaCl and B-NaCl de-icing additives worsen these three performances of bitumen,and the acceleration of NaCl is more obvious.(2)Compared to the mineral powder asphalt mixture,LDHs de-icing additives improved the anti-short-term thermal oxygen aging property of asphalt mixture,and significantly improved the road performance of asphalt mixture after thermal oxygen aging and water immersion test and thermal oxidative ageing and water immersion test,NaCl and B-NaCl de-icing additives both accelerated the short-term thermal oxygen aging of asphalt mixture,and promoted the decrease of the road performance of asphalt mixture after the long-term thermal oxidative aging and water immersion test.(3)The initial ice melting ability of three asphalt mixtures prepared by three deicing additive from high to low is NaCl,B-NaCl,LDHs de-icing additive,but after immersion test,the de-icing performance of asphalt mixing prepared by NaCl decreased significantly,as well as asphalt mixing prepared by B-NaCl de-icing additive,while the de-icing performance of asphalt mixture prepared by LDHs deicing additive basically unchanged.(4)The de-icing performance of asphalt mixture prepared by three kinds of deicing additives are decreased little after the short-term thermal oxygen aging,while after long-term thermal oxidative aging and water immersion test,ultraviolet oxidative aging and water immersion test,the de-icing properties of asphalt mixture prepared by NaCl and B-NaCl de-icing additive are greatly reduced,and the changes in de-icing properties of asphalt mixture prepared by LDHs are very little,which suggested that the asphalt mixture prepared by LDHs de-icing additive show excellent long-term de-icing properties.(5)The layered structure of LDHs de-icing additives have both the effect of physical reflection and chemical absorption to UV,and can effectively prevent the light component's volatilization and oxygen penetration into the bitumen.At the same time,the motherboard has the effect of confinement on interlayer chloride ions,thus effectively improves the resistance to thermal-oxidative aging and UV-oxidative aging,that makes the asphalt mixture good road and de-icing performance;while NaCl and B-NaCl de-icing additives can hardly prevent the light component's volatilization and the oxygen penetration of bitumen,compare with mineral powder,they accelerate the thermal-oxidative and UV-oxidative aging of bitumen.because NaCl can be easily precipitated by water,thus lead to the decrease of road and deicing performance of asphalt mixtures;through organic wrapped can reduce the aging of bitumen and prevent the precipitation of NaCl,it is conducive to the improvement of the anti-aging and durability of de-icing performance of self-deicing asphalt mixtures.