Thermo-rheological analysis of WMA-additive modified binders

Abstract

Thermo-rheological characteristics of unmodified and modified bitumen have significant impacts on the mechanical response of asphalt. This study investigates the impacts of an organic and a chemical Warm Mix Asphalt additive on bitumen thermo-rheological and mechanical characteristics. Modified binders with different concentrations of each additive were studied and analysed comparatively to a 40/60 penetration grade bitumen. Frequency sweep tests were performed at different ageing levels to characterise the Linear Viscoelastic properties. The multiple stress creep and recovery, linear amplitude sweep (LAS) and low temperature creep stiffness tests, together with the Glover-Rowe (G-R) fatigue parameter (determined from fitting of the 2S2P1D model to the complex shear modulus and phase angle master curves) were used to analyse the performance of the binders at critical operating temperatures. The results demonstrated the necessity to analyse the behavior of the studied binders beyond the limits of linear viscoelasticity to better characterise these types of bitumen. The results also indicated that both additives retarded bitumen ageing with the organic additive increasing bitumen elastic response while the chemical additive increased its viscous response. The results also showed an excellent correlation between the G-R parameter and LAS results which suggests the ability to use this parameter in characterising fatigue performance of the studied binders. This also suggests that bitumen fatigue life may be improving over time due to the increased elastic behahviour during ageing so long as a certain critical level of ageing is not reached.

Sustainable Production of WMA with Pine Gum Wax Modification: Physical and Rheological Evaluation

“…The following bitumen modi cation procedure was determined in the light of previous studies [13,21,[30][31][32][33][36][37][38].…”

“…The occurrence of excessive increase in softening point and low moisture resistance are the two problem for (S®-WMA). In light of numerous available studies [5,13,[27][28][29][30][31][32][33][34][35], solutions can be on basis of modifying WMA with additional additives. To overcome these problems, S®-WMA was prepared with S® in a 1% increase from 1-3% (by weight of bitumen).…”

Investigation of rutting, fatigue and cracking resistance parame-ters of CR modified warm asphalt binders compare with SBS modified binders

“…One of the most common warm asphalt additives is Sasobit. In studies using Sasobit additive, it is stated that Sasobit provides high rutting resistance by improving the performance of binders under high temperatures and increases the rigidity under low temperatures (Abed et al 2020;Behnood et al 2020).…”

Rutting analysis of different rubberised stone mastic asphalt mixtures: from binders to mixtures

“…The viscoelastic properties of modified binders, and particularly of rubberised binders, is fundamentally different from unmodified bitumens, and thus, more comprehensive reviews are needed to investigate them. The relationship between the linear viscous component of unmodified bitumens and the expected rutting resistance of pavement is well established in the literature [13][14][15][16][17][18][19]. The linear viscous parameters have, however, failed to effectively characterise modified binders.…”

“…The linear viscous parameters have, however, failed to effectively characterise modified binders. Modified binders have complex response to the different stress/strain levels and loading rates that may provide misleading correlations when tested under only linear conditions [19][20][21][22]. Thus, assessing the rutting properties of rubberised binders using different strain conditions that are associated with different damage mechanisms, is one objective of this study.…”