Exploring potential of Marshall-RT as simple performance test to evaluate rutting resistance of asphalt mixtures.

This study explored a new simple monotonic Marshall rutting test (Marshall-RT) to evaluate the rutting resistance of asphalt mixtures. The Marshall-RT test setup combines the Marshall fixture (at the bottom) and the IDT fixture (at the top). The rutting resistance of asphalt mixtures was evaluated using peak load (Pmax) and work done for the deformation damage obtained from the load-displacement curve. Nine plant-produced asphalt mixtures having different types of binders (unmodified, crumb rubber modified binder (CRMB)), and polymer modified binder (PMB)) and gradations having different nominal maximum aggregate sizes (NMAS) were evaluated. The Marshall-RT test parameters (i.e. Pmax and $W_{P_{{\rm max}}}$ W P m a x ) have shown a strong correlation with fundamental (i.e. Flow Number (FN)), simulative (i.e. Hamburg wheel tracking test (HWTT)), and simple monotonic (i.e. Ideal rutting test (IDEAL-RT)) rutting tests. Moreover, the Marshall-RT test has shown good repeatability, the highest differentiation potential, and consistent ranking with other rutting tests. Furthermore, for high traffic levels (i.e. 100 MSA (Million Standard Axle)), at 50°C preliminary minimum threshold criteria were proposed for Marshall-RT (Pmax and $W_{P_{{\rm max}}}$ W P m a x ), and IDEAL-RT (RTIndex) as 5 kN, 14 kN-mm, and 90, respectively, to avoid premature rutting failure. Thus, the newly developed monotonic Marshall-RT test can also be used as a surrogate simple performance test to estimate the rutting potential of asphalt mixtures during the mix design and plant production phases as quality control (QC)/quality assurance (QA). [ABSTRACT FROM AUTHOR]