Relaxation Modulus of SMA with Polymer Modified and Highly Polymer Modified Bitumen

The article presents the test results of the relaxation modulus of SMA. The samples of SMA mixture were made using polymer modified bitumen PMB 45 / 80-55 (PMB-N) and highly polymer modified bitumen PMB 45 / 80-80 (PMB-HM). Determination of the relaxation modulus were made using DT-CY test (direct tensile test) at 10 °C, 20 °C and 40 °C. To describe the relaxation phenomenon of the bituminous mixture a logit model has been used. The test results indicates that the use of the highly modified bitumen (PMB-HM) caused the increase in the stiffness modulus SMA at high temperature / low frequencies. As a result, the presence of highly polymer modified bitumen will increase the resistance to the permanent deformation of SMA.