Active Standard ASTM D6703 | Developed by Subcommittee: D04.47
Book of Standards Volume: 04.03
Historical (view previous versions of standard)
Significance and Use
5.1 This test method is intended primarily as a laboratory diagnostic tool for estimating the colloidal stability of bitumen asphalt, asphalt cross blends, aged asphalt, and heavy oil residuum. Historically, bituminous asphalt and heavy oil residua have been modeled as colloidal suspensions in which a polar associated asphaltene moiety (the dispersed phase) is suspended in a maltene solvent moiety (the dispersing medium) (refer to Test Methods D3279, D4124, and D5546 for further definition of asphalt fraction materials). The extent to which these two moieties remain in state of peptization is a measure of the compatibility (colloidal stability) of the suspension. Compatibility influences the physical properties of these materials, including rheological properties, for example, phase angle and viscosity. This test method and other similar test methods, along with the classical Heithaus test, measures the overall compatibility of a colloidal system by determining a parameter referred to as the state of peptization, P. The value of P commonly varies between 2.5 to 10 for unmodified or neat asphalts. Materials calculated to have low values of P are designated incompatible. Materials calculated to have high P values are designated compatible. Values in P are calculated as a function of two parameters that relate to the peptizability of the asphaltene moiety (the asphaltene peptizability parameter, pa) and the solvent power of the maltene moiety (the maltene peptizing power parameter, po). Values of pa and po are calculated as functions of the quantities Cmin and FRmax. Values of Cmin and FRmax are determined from experimental variables, the weight of asphalt (Wa), the volume of solvent (VS) to dissolve the weight of asphalt, and the volume of titrant (VT) added to initiate flocculation.
1.1 This test method describes a procedure for quantifying three Heithaus compatibility parameters that quantify the colloidal stability of asphalts and asphalt cross blends and aged asphalts.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D3279 Test Method for n-Heptane Insolubles
D4124 Test Method for Separation of Asphalt into Four Fractions
D5546 Test Method for Solubility of Asphalt Binders in Toluene by Centrifuge
E169 Practices for General Techniques of Ultraviolet-Visible Quantitative Analysis
ICS Number Code 17.060 (Measurement of volume, mass, density, viscosity)
UNSPSC Code 41110000(Measuring and observing and testing instruments); 30121601(Asphalt)