Use of the Monotonic Shear Strength Test to Characterize Asphalt Binders

The Monotonic Shear Strength (MOSS) Test was developed during Asphalt Institute Foundation (AIF) research project AIF 22-03 as a means of evaluating the strength and strain tolerance of asphalt binders in relation to asphalt shingle durability. Since that time, the procedure has been refined and used in a variety of applications in binder research. This paper attempts to frame a “proof of concept” for the use of the MOSS test as a viable option for (a) evaluating the ductile-to-brittle transition range of asphalt binders; (b) discriminating between yield energy for binders at isothermal conditions; (c) highlighting the strength-enhancing properties of modification not captured by testing in the linear viscoelastic range; (d) assessing aging effects and durability; and (e) providing an initial estimation of test variability. By evaluating several material types (roofing and paving grade binders with and without modification with polymers) with varying methods of analysis for fitting and interpreting data (such as toughness comparisons and indexing of materials using Critical Strain determinations), several options for use of the MOSS procedure as a failure test are presented for consideration and use.