The Effect of Exposure on Bitumens.

Abstract

I 5 3 Obtained from distillation of bitumens: This includes petroleum pitch, either "straight" or "cut back." 4 Obtained from the "oxidation" of bitumens: This includes "blown" petroleum pitches. 5 Obtained from the "sulfurization" of bitumens: This includes the so-called "Dubb's asphalt," obtained by heating petroleum residues with sulfur. 6 Variable Origin: I t may be of animal, vegetable or mineral origin and includes both natural and artificial products. 7 Hydrocarbon Complex: Often contains oxygen, nitrogen or sulfur derivatives of the hydrocarbons. This excludes vegetable resins, vegetable and animal waxes, etc. Associated with a mineral matrix: This may be calcareous, siliceous, earthy, etc., which is usually present as an impurity. Solutions in essential oils: The essential oils consisting of terpenes. IO Variable Compositions: KO exact chemical composition. Usually mixtures of closely related substances, composed of the elements carbon and hydrogen, together with varying amounts of oxygen, sulfur and nitrogen. May contain hydrocarbons, fats, fatty acids, resin acids, waxes, etc., etc., or mixtures of these. 11 Insoluble in water: This excludes gum resins, carbohydrates, etc. 12 Partly soluble in water: The carbohydrates ("gums") are the soluble constituents. l 3 Soluble in carbon disulfide, benzol, etc.: This does not take into consideration the mineral constituents present and excludes the pyro bitumens. 14 Relatively insoluble in carbon disulfide, benzol, etc.: This likewise does not take into consideration the mineral constituents present and excludes the bitumens proper, tars, and most pitches. This excludes gaseous and solid bitumens. ' 5 Viscous: 16 Viscous to semi-solid: 1: Viscous t o solid: This is governed by the amount of essential oil present. Some occur as sticky masses, others as hard and brittle solids at ordinary temperatures. Plasticity is an inherent or an acquired property. Some are plastic at ordinary temperatures, others become plastic, under the influence of heat or when combined with suitable fluxes. This excludes the gaseous and liquid bitumens, tars and oleo resins. 1' Viscous to solid Bitumens and Pyro Bitumens: This includes the hard and relatively insoluble wood-tar pitches, etc. Semi-solid to solid: Usually contains small amounts of essential oils, which govern the consistency. This excludes gaseous, liquid and viscous substances. 2" Solid: 2' Variable Hardness: 22 Light Colored in Mass: 23 Dark Colored in Mass: Csually black. This excludes paraffin (ceresine), and vegetable resins. variable Color in Mass: Color ranges from pure white (paraffin wax), to very dark, almost black (ozokerite and montan wax).

Low-Temperature Oxidation Kinetics of Asphalt Binders

“…The oxidative aging of asphalt binder has been studied for almost a century. Hubbard and Reeve examined the effects of outdoor weathering on the physical and chemical properties of paving-grade asphalt cements, finding that oxidation, and not volatilization alone, is responsible for the changes in asphalt binder properties over time (1). Subsequent studies have confirmed the Hubbard and Reeve finding (2,3).…”

Modification of Asphalt by Starch-Derived Supramolecular Fibers: A Simple Way to Tune Flow Resistance

“…During storage at room temperature for 12 h, no phase separation was observed. After standing for a period of storage, the appearance of the samples had changed slightly depending on the amount of 16AG in the mixture (Figure S1): StA alone showed a distinctive gloss, indicating a smooth surface; StA–16AG(1) showed an appearance similar to that of StA, although it was slightly matte; and StA–16AG(5) and StA–16AG(10) both showed a completely matte appearance. Atomic force microscopy revealed that the StA surface was covered with bee-like structures and terrace pattern assemblies (Figures and S2), which was consistent with a previous report. − In contrast, the surfaces of the materials containing 16AG were characterized by stripes or fiber-like structures with a width ca.…”

Understanding the Sensitivity of Mixture Cracking Performance Tests to Binder Properties and Long-Term Aging

“…Aging in asphalt pavements has been recognized and studied for almost a century. Hubbard and Reeve ( 1 ) published the results of an initial study that examined the effects of a year of outdoor weathering on the physical (weight, hardness, etc.) and chemical (solubility) properties of paving-grade asphalt cements.…”