Study On Self-healing Behavior Of Asphalt Mortar Based On Rheology

Self-healing materials are materials that have their own ability to repair damage.The self-healing behavior of asphalt materials means that during the intermittent period of loading,the asphalt molecules undergo infiltration,diffusion and other movements,so that the micro-cracks in the asphalt mixture are automatically healed.Their performance is gradually restored.Asphalt materials have a strong self-healing ability due to their ability to diffuse and flow.As a natural asphalt,rock asphalt is very stable in nature and exhibits excellent road performance and self-healing properties when it is incorporated into asphalt or asphalt mixture as a modifier.At present,the problem of fatigue cracking of asphalt pavement during its service period has been quite severe.How to make full use of the self-healing property of asphalt material to timely protect the pavement,so that the damage and cracks can be repaired in time and prolong its service life.It is an urgent problem to be solved in road engineering design and maintenance,which is of great practical significance for highway engineering.Based on the existing research results,this paper deepens the influence of various influencing factors on the self-healing behavior of asphalt materials,and initially explores the evolution of self-healing behavior during the whole interval.The main research contents and research results are as follows:(1)The temperature-dependent fatigue-healing-fatigue test was used to analyze the effect of temperature on the self-healing properties of asphalt mortar.The frequency sweep test determined the state of asphalt mortar under different temperature conditions.The above two test results indicate that the matrix asphalt mortar is high.It begins to appear as a near Newtonian fluid at its softening point and has good fluidity.The temperature at this time is the optimum self-healing temperature of the matrix asphalt mortar.The optimum self-healing temperature of the rock asphalt mortar is much lower than that of the rock asphalt modified asphalt.The softening point,and the rock asphalt mortar has obtained the maximum self-healing ability before it appears as a near Newtonian fluid.(2)The matrix asphalt mortar and rock asphalt mortar were selected to apply small strain to the damaged asphalt mortar samples in the intermittent time.The self-healing behavior was monitored.It was found that the asphalt rubber healing curve showed an overall growth trend and developed the performance.It is a"two-stage"type,that is,a growth curve with a"semi-parabolic"shape and a stable curve with a"horizontal"shape.(3)The asphalt mortar has a threshold damage degree.When the fatigue damage is less than the threshold damage degree,the asphalt mortar has the healing ability to return to the initial state;and when it is greater than the threshold damage degree,it is not easy to return to the initial state.The incorporation of rock asphalt increases the threshold damage of the asphalt mortar.(4)Through the fatigue-healing-fatigue test of two kinds of asphalt mortar under different healing time and different damage conditions,the relationship between the healing index characterized by cumulative dissipative energy and the healing time t~0.25.25 is established,and then the damage degree is obtained.The shortest healing time when matrix asphalt mortar and rock asphalt mortar are fully recovered.(5)Comparing the fatigue-healing-fatigue test and the healing monitoring test data of matrix asphalt mortar and rock asphalt mortar,it is found that the addition of rock asphalt can reduce the fluidity of asphalt mortar,but it can significantly improve the adhesion of asphalt mortar.Sexual healing intensity and efficiency.