| Asphalt pavement is a common form of road paving in China,which has a high absorption rate of solar radiation heat.In hot summer,the surface temperature of the road can reach 60-70℃,which aggravates the urban heat island effect and the rutting disease of asphalt pavement.The heat reflective coating can reduce the temperature of asphalt pavement effectively,but the problem of poor weather resistance and pollution of the coating has not been solved effectively,which limits the application of the heat reflective coating.In this study,a new type of thermal reflection composite coating was prepared from the perspective of reducing road surface temperature,enhancing the anti-fouling ability of the coating and improving the weatherability,and the cooling effect,long-term performance and road performance were studied.In this paper,the photothermal environment of asphalt pavement and the cooling mechanism of heat reflective coating were analyzed,and the feasibility of organic/inorganic composite coating was demonstrated according to the coating staining mechanism,organic/inorganic composite mechanism and silane coupling agent modification mechanism,so as to provide a basis for the selection of coating raw materials.According to the coating composition and technical requirements,the paper puts forward the main,secondary film-forming material selection principle and method of determining the pure acrylic emulsion,silicon sol,silane coupling agent KH-570 as the main film-forming material,R type Ti O2,carbon black,hollow microsphere,as a secondary film-forming substances,deionized water,dispersing agent,defoamer,film-forming agent as auxiliary film-forming material.With organic/inorganic proportion and colloidal silica particle size as control variable,the preparation of 12 different coating ratio,through the indoor cooling test cooling effect and analysis the reason,the study found that when the rate of organic/inorganic 2:3,colloidal silica particle size 30-40 nm,the maximum cooling range of the composite coating can reach11.19℃,found that the specimen surface cooling range is greater than the interior,the best coating weight is 0.6 kg/m2.The outdoor cooling test shows that the maximum cooling range of the composite coating can reach 10.66℃.Through the dust and oil pollution test to study the stain resistance of the coating,it was found that the minimum change rate of the cooling temperature range of the coating after dust and oil pollution was 5.88%and 3.75%,respectively.The coating with silica sol can suppress the coating static phenomenon and improve hydrophobic effect,improve stain resistance.The more dust is spread,the greater the effect on the cooling effect.Through coating water resistance,acid resistance,alkali resistance,outdoor weather resistance test,found no obvious adverse changes on the surface of the coating.The coating adhesion evaluation level is 1 and the hardness is 4H,which can meet the requirements of use.The anti-slip capability decreases with the increase of the coating amount,and the method of spreading 40%quartz sand before the coating is dried can improve the anti-slip performance effectively.After tire wear,compared with the coated specimen and the ordinary specimen,although the mass loss of the quartz sand specimen is the largest,it is only2.4g,and the wear resistance is good. |
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