Properties of Foamed Asphalt for Warm Mix Asphalt Applications (2015)

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81 BBR Bending Beam Rheometer – A device for measuring the low-temperature stiffness of asphalt binder. CI Coatability Index – A measure of the binder’s ability to coat aggregate particles by measuring water absorption of the coarse aggregate mixed with binder relative to the water absorption of the bare coarse aggregate. CT Computed Tomography – A method to acquire and interpret a two-dimensional x-ray image of an object to study its internal structure nondestructively. DevpSN Viscoplastic Strain at LCSN – A measure of non-recoverable deformation in the Hamburg Wheel Tracking Test. DSR Dynamic Shear Rheometer – A device to measure the shear modulus and phase angle of a substance at various temperatures and loading frequencies. ER Expansion Ratio – The volume of a foamed liquid at any point in time relative to its unfoamed volume. ERmax Maximum Expansion Ratio – The greatest volume increase experienced by a foamed liquid. FI Foamability Index – The area under the curve defined by the expansion ratio of a liquid versus time. HL Half-Life – The period between the maximum expansion ratio and one-half of the expansion ratio. HMA Hot Mix Asphalt – An asphalt mixture produced at a temperature above 275°F (135°C). HWTT Hamburg Wheel Tracking Test – A loaded-wheel method of ascertaining the strip- ping and rutting susceptibility of an asphalt mixture. IDT Indirect Tensile (Strength Test) – A test method in which a cylindrical sample of material is loaded diametrically to produce a region of uniform tensile strain in the horizontal direction. k-value Rate of Collapse of Semi-Stable Foam – The slope of the curve defined by the expansion ratio of a liquid versus time at a specific time interval. LCSN Load Cycles to Stripping Number – In the Hamburg Wheel Tracking Test, it is the number of loading repetitions at which the curve of rut depth versus loading cycles changes from negative to positive curvature. LCST Load Cycles to Remaining Life – Number of additional load cycles after LCSN needed for the rut depth accumulated by the stripping strain to reach a certain rut depth, usually 0.5 in. (12.5 mm). Abbreviations, Acronyms, and Definitions

82 LDM Laser Distance Meter – A device employing light reflection to measure length. LEA Low-Emission Asphalt – A name given to a WMA production process in which wet sand is used to create foamed asphalt binder during mixing. LMLC Laboratory Mixed, Laboratory Compacted – A type of asphalt mixture specimen where the mixture components are combined and compacted in the laboratory. MR Resilient Modulus – A repeated load indirect tension test to obtain the stiffness of a material. NAPA National Asphalt Pavement Association – A trade association of plant asphalt mix- ture producers in the United States. PAV Pressure Aging Vessel – A device for rapidly oxidizing asphalt binder to simulate approximately 5 years of field aging. PMLC Plant Mix Laboratory Compacted – A type of asphalt mixture specimen where the mixture components are combined in an asphalt mixing plant and compacted in the laboratory. RTFO Rolling Thin Film Oven – A method for simulating asphalt plant aging in the laboratory. SAI Surface Area Index – The ratio of the estimated surface area of all bubbles in a foamed liquid at a given time to the surface area of the unfoamed liquid. SGC Superpave Gyratory Compactor – A type of laboratory asphalt mixture compactor designed to produce cylindrical specimens for testing. tmax Maximum Shear Stress – In a Superpave gyratory compactor, it is the greatest level of stress generated in the horizontal plane during compaction. TSR Tensile Strength Ratio – The wet-conditioned indirect tensile strength divided by the dry indirect tensile strength. WMA Warm Mix Asphalt– An asphalt mixture produced at a mixing temperature of less than 275°F (135°C).