Study On The Road Performance Of Cement-Stabilized Macadam In Lhasa-Gonggar Airport Expressway

Lhasa-Gongga Airport Expressway is the first expressway in Tibet, where theconstructions of expressways and arterial highways were at the primary stage.Currently, research on cement-stabilized macadam base has not been initiated yet, androads in Tibet mainly consist of cement-stabilized-gravel. Previous studies oncement-stabilized-gravel base could be partly used as reference, while some of theresults were not appropriate for application. For this purpose, this study focused onthe strength formation of cement-stabilized macadam base in high-attitude regions inTibet, and conducted tests in the aspects of mechanical property, frost resistance andshrinkage performanceof the mixture of cement-stabilized macadam base, and thusprovided technical support for the construction of road base of the first expressway inthe high-altitude regions in Tibet, as well as references for further construction andrevision of the technical specification in similar regions.Through the approaches of standard curing and simulation of low-temperaturecuring in the strength tests for cement-stabilized macadam, the effects of variousfactors on the unconfined compressive strength, compressive resilient modulus,splitting strength and flexural tensile strength of the mixture were analyzed, therebythe conclusion was obtained that combined methods for minimum cement amount andcuring temperatureat4%and7℃respectively could improve the strength andmodulus of cement-stabilized macadam base.Given the low-temperature environment in high-attitude regions, this study testedstrength changes of cement-stabilized macadam base during the process offreezing-thaw cycling. To ensure that the cement-stabilized macadam baseshowedbetterfrost resistance so that was able to adapt to the low-temperature environment inTibet, it is therefore suggested that the minimum cement amount should be4%, andthe base curing temperature should be above10℃.The experiments comprehensively analyzed the influences of curing age, theamount of cement, temperature and moisture on the maximum shrinkage stress fromthe view of solving the problem of drying shrinkage of cement-stabilized macadam base, and consequently proposed the critical measures that it would improve theresistance performance of drying, shrinkage and cracking for bases that strictlycontrolling the water content for each raw material.In this study, we have paved test road in the new construction of Lhasa-GonggaAirport Accommodation Expressway. Through comparing the practical applicationeffect with indoor testing effect, the road performance of cement-stabilized macadambase was further investigated, and the corresponding conclusions of indoorexperiments were tested and verified.