Study On Self-Healing Performance Of Basalt Fiber Asphalt Mixture Under Complex Road Environment

Fatigue failure of asphalt pavement is mainly caused by excessive accumulated strain caused by long-term use of asphalt pavement,the main manifestation is pavement cracking.In 1967,Bazin and Saunier tests proved that asphalt mixture has self-healing ability.Inorganic mineral fiber additives have the advantages of stable chemical properties,natural environmental protection,obvious improvement of pavement performance and low price,among which basalt fiber is the best one.Therefore,it has quickly become an important research object of road surface fiber modifiers.In recent years,it has been proved that the self-healing performance of basalt fiber asphalt mixture is in a simple experimental environment.Compared with the base asphalt mixture,it has a great improvement.However,there are few researches on the self-healing performance of basalt fiber asphalt mixture under the influence of complex road environment.Therefore,the selfhealing performance of basalt fiber asphalt mixture in complex road environment is studied in this paper.Firstly,the four-point bending fatigue test of AC-16 C,SBS modified asphalt mixture and basalt fiber asphalt mixture was carried out under the same conventional test conditions,and the damage degree was observed.The fatigue life of three kinds of asphalt mixture is determined and the damage degree of subsequent test is determined.Then,three kinds of asphalt mixture specimens were subjected to short-term aging,long-term aging,ultraviolet aging,snow melting agent immersion and freeze-thaw cycle treatment,and then "fatigue-self-healing-fatigue" test was carried out.By analyzing the data of two fatigue tests before and after,the damage rate and healing index were used as self-healing properties.Can evaluate the self-healing ability of different mixture in different road environment.It was found that long-term aging was the most important factor affecting the self-healing of the mixture,followed by freeze-thaw cycle and ultraviolet aging,and that the short-term aging and snow melting agent had the least effect on it.Finally,the microcosmic observation of matrix asphalt mixture,SBS modified asphalt mixture and basalt fiber asphalt mixture was carried out by means of electron scanning microscope(SEM).In order to explain the influence of basalt fiber on the self-healing characteristics of asphalt mixture,the mechanism of reinforcing effect of basalt fiber on asphalt mixture is analyzed from the microscopic point of view.The purpose of this study is to simulate the actual use of the road environment,through fatigue self-healing test comparative analysis of common matrix asphalt mixture,SBS modified asphalt mixture and basalt fiber asphalt mixture in different road environment of self-healing characteristics,So as to provide relevant theoretical basis for practical engineering maintenance.