Permanent deformation performance and a nonlinear constitutive model with thermal-mechanical coupling of PCPMA mixture

Polymers cracking products modified asphalt (PCPMA) pavement is a new warm mixing pavement technology. The permanent deformation properties of three types of PCPMA mixture were studied using repeated load triaxial (RLT) tests at different temperatures and deviator stress levels. The half sine wave intermittent load was adopted to simulate the vehicle load on the actual pavement. The test results indicate that the permanent deformation of the PCPMA mixture is increased gradually with the increase of temperature and stress level at the same load times. A robust skeleton structure can improve a specific resistance to the deformation of the PCPMA mixture. A 'three-stage' deformation characteristics, which are transfer section, stabilization section, and destruction section in proper order, exhibited under high temperature and significant stress level. For the condition of lower temperature and smaller stress levels, the permanent deformation only accumulates in the first two stages. The PCPMA was only damaged at 50 degrees C and 0.7 MPa, which has better durability than the matrix asphalt mixture. Accumulative residue viscoelastic strain and viscoplastic strain are derived from RLT test results. And then, a new viscoplastic mechanical model is proposed to predict the permanent deformation of the PCPMA mixture at different conditions, considering the nonlinear characteristics. Furthermore, this new mechanic model, which realized the unification of three and two stages deformation law of PCPMA mixture, may be effectively used for mechanical analysis and permanent deformation calculation of PCPMA pavement.

Automated summary

PCPMA mixture with a robust skeleton structure shows different permanent deformation characteristics under different temperatures and stress levels. A newly proposed viscoplastic mechanical model can predict the permanent deformation of PCPMA mixture under various conditions, providing an effective means for mechanical analysis and permanent deformation calculation of PCPMA pavement.