High temperature rheological properties of high modulus asphalt cement (HMAC) and its definition criteria

Abstract In order to study the high temperature rheological properties of high modulus asphalt cement (HMAC) and clarify its definition criteria, firstly, three kinds of HMAC binders were prepared with high modulus modifiers and subjected to dynamic shear rheological test (DSR), zero shear viscosity test (ZSV) and multi-stress creep recovery test (MSCR). Based on the tests and analysis, the complex shear modulus (G*), rutting factor (G*/sin δ), zero shear viscosity (ZSV) and unrecoverable creep compliance (Jnr) were taken as technical indexes for the performance evaluation of HMAC. Further, through analyzing the consistency of evaluation results of different evaluation indicators and the correlation between evaluation indicators of HMAC binders and HMAC mixtures, the definition criteria of HMAC binder are eventually given. The test results show that the three high modulus modifiers can improve the viscoelastic properties and high temperature properties of the matrix asphalt, but the modification effect is slightly different; the rheological properties index can basically make a consistent evaluation of the high temperature performance of three kinds of HMAC binders, but the correlation degree is different. The dynamic stability (DS) of the mixture is well correlated with G* (60 °C, 10 Hz, 0.1%) (refers to the complex shear modulus measured at 60 °C, loading frequency 10 Hz and strain level 0.1%), G*/sin δ (76 °C, 5 Hz, 0.1%) (refers to the rutting factor measured at 76 °C, loading frequency 5 Hz and strain level 0.1%), zero shear viscosity (60 °C) and Jnr.3.2 (76 °C) (refers to the unrecoverable creep compliance measured at the stress level of 3.2kpa and the temperature of 76 °C), but the correlation of dynamic modulus (E*) with zero shear viscosity (60 °C) and Jnr.3.2 (76 °C) is poor. In summary, it is recommended that HMAC binder should meet both G*(60 °C, 10 Hz, 0.1%) ≥ 60.0 kPa and G*/sin δ (76 °C, 5 Hz, 0.1%) ≥ 5.0 kPa, and the definition criteria can be as a design basis for HMAC binder. At the same time, it is recommended to use Jnr.3.2 (76 °C) to evaluate the high temperature performance of HMAC.