Zoorob, Salah E.Mturi, Georges A.Sangiorgi, CesareAlmeida, Marisa S. DinisHabib, Noor Zainab2020-01-222020-01-222018-01-15Salah E Zoorob, Georges A Mturi, Cesare Sangiorgi, Marisa Dinis-Almeida, Noor Zainab Habib. (2018). Fluxing as a new tool for bitumen rheological characterization and the use of time-concentration shift factor (ac), Construction and Building Materials, 2018, vol. 158, pp. 691-699. https://doi.org/10.1016/j.conbuildmat.2017.10.020http://hdl.handle.net/10400.6/8572The concept of temperature shift factor (aT) as defined by Doolittle, relating the free volume of a vis-coelastic material at the current and reference states is briefly examined together with the resultantWilliam-Landel-Ferry equation. This paper highlights the fact that change in free volume arise not onlyfrom temperature variations but can also result from the absorption of solvents and thus a generalizedDoolittle relation may also be applied to a solvent concentration shift factor (ac). To validate this concept,a small scale laboratory investigation was carried out by blending 40/60 penetration grade bitumen withvarious proportions of one type of cooking oil and conducting dynamic shear rheometer frequencysweeps at a range of temperatures. By applying time-concentration superposition to each flux content,it was possible to shift horizontally (ac) each set of complex modulus data measured at each test temper-ature, so that all sets superimpose onto the master curve of the base bitumen at a preselected referencetemperature. A direct relationship between conventional time-temperature shift and the proposed time-concentration shift factors was thus demonstrated using a sample of penetration grade bitumen and onetype of vegetable oil. Further experimentation with other bitumen-flux combinations is necessary priorto recommending general adoption of the proposed tool.engBitumen rheological characterizationTime-temperature superpositionTime-concentration superpositionBitumen fluxingFree volume shiftingjournal article10.1016/j.conbuildmat.2017.10.020