Material Composition Design And Performance Of High Friction Surface Treatment Based On Differential Polishing

As a result of prolonged exposure to factors such as traffic load and environmental conditions,the skid-resistance structure on the surface of cement concrete pavement is subject to continuous wear.This results in a decrease in the friction coefficient and a significant deterioration in pavement surface performance,even to the point of complete loss of functionality well before reaching its designed service life.Such degradation not only impacts driving comfort but also compromises safe driving conditions.Consequently,there is an urgent need to improve the long-term skid resistance of cement pavement.High Friction Surface Treatment(HFST)is an emerging preventive maintenance technology that has demonstrated its significant potential for improving pavement surface characteristics and enhancing driving safety through numerous domestic and international engineering practices.The implementation of this preventive maintenance measure on cement pavement with suboptimal skid resistance to restore pavement road functionality is of practical significance for ensuring traffic safety.However,current research on the modification and composition optimization of polymer adhesives used in HFST,the applicability of blended aggregates design to HFST,and the attenuation of key service performance of HFST have yet to be elucidated.Therefore,this paper has first modified traditional epoxy resin material and optimized component proportions to prepare a toughened,high-fluidity epoxy resin adhesive system suitable for cement pavement maintenance.The bonding performance of modified epoxy resin adhesive material with the cement substrate surface and aggregates was explored.Secondly,the physical and mechanical properties,chemical and mineral composition,and microstructure of 88#calcined bauxite and limestone aggregates were comparatively studied to analyze the mechanism of differential-polishing effects generated by the two aggregates.Based on the differential-polishing principle,these two aggregates were blended for use in HFST to investigate texture evolution and attenuation law of skid resistance during simulated long-term traffic polishing.The correlation analyses of texture change and skid resistance attenuation were carried out.Finally,wear stripping tests,freeze-thaw cycle tests,and UV aging tests were conducted on HFST to analyze its stripping resistance and weather resistance,which further evaluate its service durability.The primary conclusions drawn are as follows:(1)The optimal ratio range for a modified epoxy resin adhesive system has been determined to be E51 epoxy resin:curing agent:toughening agent:diluent=100:30～35:20～30:5.Under this ratio,the epoxy resin adhesive system has low viscosity and high fluidity before curing,making it favorable construction workability.After curing,the system has a certain strength and excellent toughness,making it suitable for the maintenance and repair of old pavement.Micro-mechanism analysis has shown a sufficient chemical reaction between each component of the modified epoxy adhesive solution.It was equipped with stable performance,and rubber particles were uniformly dispersed in the epoxy resin system.(2)The modification of the epoxy resin system has a positive effect on its bonding and adhesion performance.The modified epoxy resin adhesive system has improved the pull-out and shear strength between the cement substrate surface and the aggregate,which significantly enhances the interlayer and aggregates’entirety bonding performance of the High Friction Surface(HFS).Based on the results of pull-out and shear tests,it is recommended that the amount of modified epoxy resin adhesive material for a single-layer HFS should be controlled at 1.0～1.2 kg/m~2,and the amount of aggregate should be controlled at 3.3～4.3 kg/m~2.For a double-layer HFS,the amount of modified epoxy resin adhesive material applied to the top layer should be appropriately increased by 0.2～0.4 kg/m~2 compared to its amount in a single-layer HFS,and the amount of aggregate should be increased by 0.7～1.4 kg/m~2.(3)The compressive performance,wear resistance,and polish resistance of 88#calcined bauxite are significantly better than those of limestone aggregate.It has excellent skid resistance and wear resistance,which can resist long-term traffic load.There are significant differences in the chemical and mineral composition,mechanical properties of each mineral crystal,as well as microcrystal structure and micro-texture characteristics between the two aggregates.The difference at the microscopic level is the fundamental reason for the huge difference in skid resistance and wear resistance between these two aggregates.It also provides a theoretical feasibility basis for the two aggregates to be blended to form a significant differential-polishing effect.(4)Under the effect of long-term traffic polishing,HFS with aggregates blending exhibits a fluctuating attenuation change law while maintaining a relatively excellent level of skid resistance.The differential polishing occurred between the two aggregates in the long-term polishing process,reducing the wear loss of the HFS aggregate.By continuously constructing and changing the macro and micro texture structure through forming“texture construction difference”between aggregates to maintain good surface roughness,it can effectively slow the attenuation rate of HFS skid resistance and improve its skid-resistance durability.The best proportion of the range of limestone replacing 88#calcined bauxite is 25%～50%.Correlation analysis shows that textures with wavelengths above 0.7mm and 1.1mm have been well correlated withμ40 andμ60,respectively.(5)In long-term accelerated wear cycles,the HFS prepared with the modified epoxy resin system has exhibited low aggregate-stripping loss and no surface layer stripping under normal tire pressure load,with better anti-wear-stripping performance.However,larger tire pressure will exacerbate the stripping failure of HFS.The HFS prepared with the modified epoxy resin system undergoing 28 freeze-thaw cycles and equivalent 5 years of ultraviolet radiation,respectively,has shown no obvious disease,and the attenuation degree of bonding performance was relatively lower.HFS still has high bond strength after the tests,so it is characterized by excellent weather resistance.