Analysis For Performance And Damage Characteristics Of Low-cement Grading Macadam Stabilized Graded Crushed Stone Base Material

In China,the ‘thin surface with strong foundation’ theory has been the basic principle of asphalt pavement for many years,which means lower cost based on the thinner surface.For example,the bituminous pavement with cement stabilized macadam semi-rigid base is the most representative one.But semi-rigid base cracks easily under seasonal environment temperature and repeated vehicleload.It brings reflective crack and shortening of service life,and there are problems here such as early damage and roadbed crack.As the bituminous pavement with cement stabilized macadam semi-rigid base is widely used,base-course material should be optimized.For this reason,a new-typed pavement: the bituminous pavement with low cement crushed stones base come out,by the analysis of early damage of semi-rigid base and research of asphalt pavement of graded crushed stone base.The research aims at providing experimental theory and technical support of application of the material in engineering.In this article,mechanical properties analysis and CT scanning technique are used to research the relationship between road performance(through internal damage and compressive strength)and temperature.And the analysis of microscopic damage law is verified by the later detection(include damage rate,flatness,deflection value)of Baoshang Road in FUSHUN.All of this provide new direction of later research of road base material and provide strong basis for actual project.(1)Make samples of paving materials,grading by screen test,and conclude optimum water content and maximum dry density.Experiment mechanical properties on low-cement grading macadam and cement-stabilized crushed macadam samples,and analyze pavement performance of the two samples,finally conclude the best cement content of low-cement grading macadam of test road.(2)Measure the compressive strength of low-cement grading crushed macadam samples between-30℃ and 30℃,by taking the experimental method of normal concrete as reference.And it shows that compressive strength decreases with temperature decreases.Ployfit the data of temperature and compressive strength,and compare the compressive strength of samples with cement stabilized macadam,conclude that,samples with lower temperature have better pressure resistance.(3)With the CT scanning technique,analyze the image of low-cement grading macadam and cement-stabilized crushed macadam samples between-30℃ and 30℃,and conclude that,pore of low-cement grading macadam occurs at transition layer between coarse aggregate and fine aggregate,and the pore and crack decrease with the temperature decrease.With the Image Pro 6.0 software,analyze the damage rate of low-cement grading macadam by binary image,and get the damage rate of different layer at different temperature,and conclude the factor of damage rate and the temperature threshold of maximum influences.Ployfit the relationship between internal damage and compressive strength.Through the Grubbs test,conclude the relationship of average aperture,maximum aperture and pore number of samples at different temperature of different layer.(4)Later detection of Baoshang Road in FUSHUN from flatness,deflection and damage rate shows that low-cement grading macadam can meet the project requirements,and the actual condition match well with the conclusion of the experiment,and low-cement grading macadam material has a much better ability of anti-damage than the cement-stabilized crushed macadam material.After taking project cost,maintenance cost and society benefit into consideration,we can conclude that low-cement grading macadam material should be widely spread,based on its excellent performance and better economical efficiency.