Asphalt Emulsion Tests: A Comprehensive Guide
Asphalt Emulsion Tests
Electrical Charge Test
This test determines the electrical polarity of asphalt emulsion globules to identify if they are anionic (negative charge) or cationic (positive charge). An electrical current is induced through the emulsion using two electrodes, and the attraction of asphalt globules to the electrodes is observed.
pH Test
This test determines the potential hydrogen (pH) of the emulsion to identify the type: anionic emulsions are alkaline, while cationic emulsions are acidic. The pH value, measured using a potentiometer, indicates the degree of acidity or alkalinity in the aqueous phase. A value of 0-7 indicates acidity (cationic), while a value of 7-14 indicates alkalinity (anionic). This test also provides insights into the emulsion’s behavior with stone materials.
Demulsibility Test
This test estimates the ease with which asphalt emulsions break, determining the time available to incorporate the emulsion during asphalt mixture preparation. The procedure involves determining the percentage of asphalt emulsion material, diluted with a calcium chloride or sodium dioctyl sulfosuccinate solution (depending on the electrical charge), retained in a 1.4 mm mesh aperture compared to the wasted asphalt emulsion.
Miscibility Test with Portland Cement
This test estimates the stability of slow-breaking asphalt emulsions when mixed with fine material. A specific amount of Portland cement is added to the emulsion, along with distilled water, through a mixing process. After a set time, the proportion of asphalt cement retained in a No. 14 mesh from the broken emulsion is determined.
Stone Coverage Test
This test estimates the stability of emulsions during asphalt mixture preparation by assessing the ease of emulsion incorporation into the stone and the formation of a resistant film that covers the mixture and withstands water action. A mixture of asphalt emulsion and wet or dry stone material (preferably limestone) is prepared under specific conditions and subjected to a water washing process. The final coverage of the stone with asphalt is then estimated. This test also helps identify the emulsion type by breaking it and can determine the emulsion’s characteristics and adhesiveness with other stone materials of various origins.
Residue by Distillation Test
This test determines the residue by distillation, water content, and solvent content in anionic asphalt emulsions. A sample of asphalt emulsion is distilled at a maximum temperature of 260 degrees Celsius to separate the emulsion into water, solvents, and asphalt residue. Further tests are performed on the residue to identify the emulsion. If necessary, the solvent is separated from a representative portion of sufficient size for identification.
Evaporation Residue Content Test
This test determines the proportion of asphalt material obtained by subjecting the emulsion to an evaporation process in an oven. Penetration and ductility tests can be performed on the residue, although the results may be lower than those obtained from distillation residues. However, these results provide an idea of the residue’s characteristics.
Saybolt-Furol Viscosity Test
This test tracks the consistency and flow characteristics of anionic asphalt emulsions at temperatures of 25 and 50 degrees centigrade. The test can be performed at other temperatures to study the emulsion’s susceptibility to heat. The time taken for 60 cubic centimeters of asphalt emulsion to move through a Furol hole installed in an upright Saybolt viscosity tube under specified load conditions is determined.
Settlement Test
This test determines the degree of homogeneity retained by cationic or anionic asphalt emulsions after prolonged storage. Samples of asphalt emulsion are left for a specified time, and the difference in asphalt concentration at different levels of the sample is determined.
Retained on Mesh No. 0.850 Test
This test involves passing a specific amount of emulsion through a No. 0.850 mesh and measuring the percentage of asphalt retained on the mesh. The result estimates the emulsion’s uniformity.
Specific Gravity Test
This test determines the relationship between the weight of a given volume of emulsion at 25 degrees Celsius and an equal volume of water at the same temperature.
Cationic Asphalt Emulsion Identification Test
This test identifies cationic asphalt emulsions by observing the surfaces of particles not covered by an asphalt film in mixtures developed with Ottawa sand, Type 3 Portland cement, and cationic asphalt emulsion.
nic asphalt emulsion.