The Leaching Characteristics Of Emulsified Asphalt And Mixture In Water

In order to study the leaching properties of emulsified asphalt and mixture in water,some common methods of analytical chemistry, such as infrared spectroscopy, colorimetricanalysis, titration analysis, gravimetric analysis, AC impedance techniques and so all, hadbeen introduced to emulsified asphalt leaching performance appraisal. The chemical oxygendemand (COD) value, suspended solids (SS) value, total hardness and emulsifier contentvalue of the soaking water were used as leaching performance evaluations of emulsifiedasphalt in water. The electrochemical impedance spectroscopy (EIS) was used asimpermeability performances evaluation of emulsified asphalt. The infrared spectroscopy(IR) spectrum was used determining the change of emulsified asphalt material after theleaching, the leaching rate was measured by weight analysis techniques and the emulsifiedasphalt leaching kinetics equation was established, too.The soaking test of the cationic emulsified asphalt, anionic emulsified asphalt andcationic emulsified asphalt cold recycled mixture in the acidic water and alkaline waterwere actualized, the soaking water and the emulsified asphalt after soaking were analysisedby the COD, SS, EIS, IR and other testing means, the results showed that:1) The SS value can be used to evaluate suspended bituminous component of leached,the COD value before the filter can be used to evaluate the mass of total organic componentof leached, the COD value ofter the filter can be used to evaluate the mass of solubleorganic components of leached, and the test of the emulsifier content can be used toevaluate the amount of leaching emulsifier. The acidic water environment would exacerbatethe leaching characteristics of the cationic emulsified asphalt. The alkaline waterenvironment would exacerbate the leaching characteristics of the anionic emulsified asphalt.The water erosion of anionic emulsified asphalt is poor, but the cationic emulsified asphaltis just the opposite.2) The soaking process of emulsified asphalt specimen in acidic water were dividedinto three stages by the EIS test results, the first stage is called initial-soaking, it’s at0h-36h.The second stage, from39h to78h, is mid-soaking. The third stage, after78h, islate-soaking. During this stage the solution through microchannel in asphalt membrane diffusion to internal of the asphalt membrane. Into the mid-stage, the asphalt membranestart to blistering and swelling. When the soaking into the third stage, then the asphaltmembrane start a large area of blistering, swelling and peeling from the metal electrodesurface, has basically lost adhesion.3) The leaching process could be divided into three stages by leaching kinetics analysis,too. On the base of the kinetic analysis the first stage of the leaching rate can be simulatedthrough a linear function, it’s vI16.980.33t. The second stage rate can be modeled as alinear function also, the function is vII8.950.11t. It is more accurate simulations that aquadratic polynomial function be used in the third stage leaching rate function,isvIII209.345.94t0.04t2.4) The results of IR shown that the composition of the cationic emulsified asphaltbefore and after soaking did not change, but there is a certain of change of the componentsproportion; The conventional index test results show that some of the changes can be seenon the penetration, softening point and ductility of the emulsified asphalt before and aftersoaking, which the degree of penetration and ductility with extension of soaking time wasreduced, but the softening point showed an increasing trend. The other experimental resultsshows that soaking has some influence on the splitting strength, cold bending and hightemperature rutting of the emulsified asphalt cold recycled mixture. Along with theextension of soaking time, the splitting strength, low temperature performance and hightemperature performance of the mixture are poorer.