Study On Design And Performance Of Asphalt Mixture In Dalian Airport

Recently,the civil aviation transportation industry has entered a stage of rapid development.With the increasing in air traffic volume and the proportion of largescale aircraft,the cement concrete pavement structure of airport runway constructed in early years in China is seriously damaged,affecting the safety and comfort of airport operation.Therefore,in the process of airport runway reconstruction or new construction,asphalt pavement has received more and more attention.The reasonable choice of mixture is especially important for the quality of asphalt pavement.Based on Dalian Airport Project,combined with indoor test and on-site construction,the design and performance evaluation of asphalt mixture is studied through mix material selection,mix gradation design,mix performance verification and mix site paving,in order to provide reference for airport asphalt pavement mixture design.Firstly,SBS modified asphalt and SBS/high modulus composite modified asphalt are prepared by using airport special 90# asphalt.The influence of high modulus agent on the dynamic viscosity of SBS modified asphalt is analyzed.And the content of high modulus agent is determined to be 3% based on engineering experience.The conventional properties and rheological properties of SBS modified asphalt and SBS/high modulus composite modified asphalt are compared and analyzed.In view of various properties,SBS/high modulus composite modified asphalt is recommended as a priority in this paper.Secondly,for the upper and lower layer of the airport pavement,three gradations are selected to design the optimum gradation,at which the optimal asphalt dosage is determined.Combined with the engineering experience,the change rules of the Marshall physical index,high temperature performance and low temperature performance indexes of the mixture under different admixture content are analyzed.The optimum dosage of anti-rutting agent(ratio to asphalt mixture)is 0.4%,and the optimum dosage of high modulus agent(ratio to asphalt dosage)is 13.5%.Then,the pavement performance of asphalt mixtures before and after adding anti-rutting agent and high modulus agent are compared.For high temperature performance,anti-rutting agent and high modulus agent can improve the dynamic stability of asphalt mixture remarkably.According to flexural strain,stiffness modulus and fracture energy,anti-rutting agent and high modulus agent can improve the low temperature performance of the mixture,but the increase range is about 10%,which is far less than the improvement effect of high temperature performance.From the residual Marshall stability MS and freeze-thaw splitting strength ratio TSR,the improvement range of Anti-rutting agent and high modulus agent on the water stability of the mixture is about 10%.For the permeability coefficient,the antipermeability of SMA16 mixture and AC20 mixture increase by 40.1% and 31.4% respectively after adding admixture.Considering the indoor pavement performance of various mixtures,the use of Anti-rutting agent and high modulus agent in the scheme make a certain improvement on the pavement performance.Finally,the actual project laying and testing are carried out.After paving,the flatness,thickness,compaction degree and water permeability coefficient are tested in time.The test results show that the paving effect is good.