Study On The Strength Controlling Standard For Cement Stabilized Gavel

Due to many benefits of cement stabilized gavel, good intensity, therigidity and integrity, good water stability and anti-frozen, wide source, it is widely used in the base. But for the understanding of cement-stabilized gravel base material intensity standard still has some weakness. Bottom tensile stress as the standard is stipulated inSpecifications for Design of Highway Asphalt Pavement (JTG D50-2006), Compressive strength is used as the standard in material composition design and engineering quality. But unconfined compressive strength tested in laboratory nearly has no relation with tensile stress of semi-rigid base's bottom. Base on theoretical research and systematically laboratory tests of cement stabilized gravel, the proper strength controlling standards and specification were put forward, this made the standards in design phase can also be used in the construction phase.Firstly, the strength formation mechanism of cement stabilized gravel was analyzed by theoretical research. The main factors which influence the strength of the material was identified, the mechanical properties of the material was studied by large amounts of laboratory tests and the variation rule of the material's strength was expressed.Secondly, calculation through fatigue equation indicates that fatigue life of the asphalt pavements are usually longer than that of semi-rigid base. The results indicate that structure design of such semi-rigid pavements depends on the tensile stress of the semi-rigid base's bottom. By orthogonal tests, the stress ratio and variation rule of tensile stress of semi-rigid base's bottom was analyzed thoroughly.Then, theoretical analysis was done on the strength specification of cement stabilized gravel, splitting strength was seen as a quite satisfying specification for this material. Base on the variation rule of the material's splitting strength, the tensile stress of semi-rigid base's bottom and Unconfined Compressive Strength standards in the Design Specification of Asphalt Pavement, splitting strength standards for cement stabilized gravel was put forward.Finally, splitting strength standards was used in a semi-rigid pavement test road, the results are quite satisfying.Splitting strength standards for semi-rigid material was put forward in the thesis. The research will be useful for the design and construction of such pavements, and will have a significant influence on the improvement of cement stabilized gravel's durability.