Mechanism Analysis And Material Design Research Of Anti-freezing Fog Seal Of Asphalt Pavement

Road freezing in winter will greatly reduce the skid resistance of road surface and affect the driving safety.Anti-freezing fog seal is a kind of coating with anti freeze and skid resistance,which is formed by emulsified asphalt as carrier and added with anti freeze agent.There is still little research on anti-freezing fog seal materials,and lack of relevant research on the mechanism of antifreeze and research on the stability mechanism of anti-freezing fog seal emulsion makes the design of anti-freezing fog seal material limited.This paper analyzes the mechanism of antifreeze of anti-freezing fog seal based on the dilute solution law and the low melting point,analyzes the release mechanism of antifreeze by the theory of pharmacokinetics,analyzes the stability mechanism of anti-freezing fog seal emulsion based on the theory of emulsion.Mixing different kinds of acetate with anionic and cationic emulsified asphalt,through the solidification test and the stability mechanism analysis of emulsion,it is determined that calcium acetate is used as antifreeze,and cationic emulsified asphalt is used as the carrier of antifreeze.Based on pharmacokinetics principle and Ritger-Peppas equation,the Peppas equation is used to fit the test results of the release of accumulated antifreeze.The release mechanism index n is found to be stable and correlated well,it is indicated that the release of antifreeze is rational with the principle of pharmacokinetics,the release of calcium acetate from the anti fogging seal layer follows the Fick diffusion mechanism,the surface structure of asphalt mixture reduces the diffusion mechanism factor n,the diffusion mechanism is not obvious with the change of antifreeze/asphalt ratio and temperature.Based on the mechanism of using solid particles to stabilize the emulsion,choosing unmodified nano-SiO2 and nano-CaCO3 to mixture with different antifreeze concentration emulsion,through the stability observation of 10d and the stability of 5d storage stability,the influence of the two materials on the stability of the emulsion is analyzed.Nano-CaCO3 was selected as an additional stabilizer.By observing and the ice-crushing force tests on the surface of the asphalt mixture coated with anti-freezing fog seal.The antifreeze effect of the coating with different antifreeze content were compared,and the source of the anti-freeze effect is analyzed by combining the ice surface phenomenon and the anti-freezing mechanism,the results shows that the higher the anti-freeze agent content,the better the anti-freezing effect.The liquid foams of antifreeze solution which do not reached the low melting point in the ice are the main source of frost protection.Based on the meteorological data of the actual freezing disaster area,the accelerated attenuation simulation method for the design of frost resistance is designed.The cumulative release test of the antifreeze during the simulation period is conducted and the ice-crushing force tests are performed on specimens subjected to different simulation periods,The results show that the prepared anti-freezing fog seal can maintain a lasting anti-freeze effect of about 90 days in winter.