Study On The Properties Of Asphalt Mixture And Its Failure Mechanism Under Freeze-thaw Cycles With Deicers

The enormous use of chlorine salt is still the main way to clear away ice and snow on the road in China,and that not only affects ecological environment but accelerates deterioration of asphalt pavement.Meanwhile,the test method for deicing performance of dicers is simple and only has a single evaluation index.It can not comprehensively evaluate deicing performance of dicers.Therefore,it is important to evaluate the deicing performance of dicers and study the properties and failure mechanism of the asphalt mixture under freeze-thaw cycles with deicer.Ultimatly,selecting a kind of dicers which has little pollution to environment,has light damage to asphalt pavement and good deicing performance.In this paper,the AC-13 SBS modified asphalt mixture is used as the research object which is commonly used in the asphalt pavement.Focusing on the problems,the evaluation system of deicing performance was established firstly which was based on the research on the deicing mechanism and deicing performance of dicers.And then the changes of mechanical property and pavement performance of asphalt mixture under the freeze–thaw cycles with deicer solution were studied,and which is the main factor of influencing it was analyzed.The mechanism of deicer-frost deterioration of asphalt mixture was revealed.Finally,GM(1,N)prediction model of gray theory was carried out to make a prediction of AC-13 SBS modified asphalt mixture anti deicer-frost deterioration properties under the freezing–thawing cycles with deicer solution which was selected by the comprehensive judgment principle from Fuzzy Mathematics.Based on systematic research,this paper draws some results were as follows:(1)The evaluation system of deicing performance was established,which have two evaluation index of ice melting performance and ice peneteation performance.Under the condition of-5?,the experimental amount of solid deicer was 1.795g(9g/m2),and the concentration of liquid deicer was 15% can show good deicing performance.The use of deicer should be prevention first and spreading in advance and that the amount of deicer was recommended.(2)The mechanical properties and road performance of asphalt mixture gradually decay under the freez–thaw cycles with deicer solution.Among all the influencing factors,the degree of freeze-thaw cycles was the most affected,the type of deicers was the second,and the concentration of deicer was the least.(3)The effect of the type of deicers on the freeze-thaw splitting tensile strength ratio is sodium chloride> calcium chloride> mixed deicer(sodium chloride: calcium chloride: sodium acetate = 1: 1: 2)> sodium acetate.When the concentration of deicer is 10%,the freezing–thawing splitting tensile strength ratio tends to be flat.(4)The deicer-frost deterioration of asphalt mixture is the result of the combined effect of the icing swelling of deicer solution,the swelling of salt crystal and the deicer solution erosion,and the icing swelling of deicer solution plays a major role.(5)The results of the comprehensive evaluation of the four kinds of deicers using the Fuzzy theoretical model were sodium acetate> mixed deicing agent(sodium chloride,calcium chloride,sodium acetate = 1: 1: 2)> calcium chloride> sodium chloride.(6)According to the GM(1,N)prediction model of gray theory,the splitting tensile strength ratio after 15 cycles of freeze–thaw was used as standard of anti deicer-frost deterioration property of AC-13 SBS modified asphalt mixture that is TSR(15 times)>82%.