Investigation of Mechanical Properties, Stiffness, and Flexibility of Cold Recycled Cement-Stabilized Gravel Base Milling Mixes with Foamed Asphalt

With the growth of service time, semirigid base asphalt pavements have gradually entered the maintenance and reconstruction period. Therefore, the treatment of waste semirigid bases has become an important issue. In this paper, based on the analysis of the properties of cement-stabilized gravel milling material, the waste semirigid base material is cold recycled using foam asphalt. The mechanical properties of the cold recycled mixture of foamed asphalt formed by 100% cement-stabilized gravel milling material (FACRM-CM) were evaluated by splitting strength test, compressive modulus of resilience test, and dynamic modulus test. The softening mechanism of the semirigid base milling material was investigated from a microscopic point of view with the aid of scanning electron microscopy (SEM). The results indicate that FACRM-CM exhibits adequate mechanical strength for use in road base layers. When semirigid base milling materials are cold recycled using foam asphalt, the stiffness of the resulting mixture decreases, whereas its flexibility increases. The results of this research can be applied to the regeneration of semirigid bases, realizing the transformation of the base from rigidity to flexibility and reducing pavement diseases.