ASPHALT BINDERS AND ASPHALT MIXTURES - Materials for Civil and Construction Engineers - page 347

anionic and cationic are produced These emulsions have negative and
positive charges respectively. Depending on the emulsion concentration,
the set or break time is varied from rapid to medium to slow set. Rapid-
setting emulsion sets in about 5 to 10 minutes, medium-setting emulsion
sets in several hours, and slow-setting emulsion sets in a few months.
The viscosity of the emulsion is rated as normal flow or slow flow, based
on the Saybolt-Furol viscosity (Figure 9.21). The consistency of the as-
phalt in the emulsion is evaluated with the penetration test. Asphalt
residues with a penetration of 100-200 are typically used. However soft
asphalts, with a penetration of greater than 200, or hard asphalts, with
a penetration of 60-100, may be used.
Asphalt emulsion types are designated based on the setting rate as RS,
MS or SS for rapid, medium, and slow set respectively. If a cationic emul-
sifying agent was used, the set designation is preceded by a C (e.g., a cationic
rapid set emulsion is designated as CRS). If the first letter of the emulsion
type is not a C, then it is an anionic emulsion. The flow rate of the emul-
sion is designated next with a 1 or 2 for a normal or slow flow respectively.
Finally, the consistency of the asphalt is identified. Not all possible combi-
nations of charge type, set rate, viscosity, and asphalt hardness are pro-
duced. Table 9.7 is a summary of the emulsion grades and types (Jansich and
Gaillard, 1998).
Other emulsion types are also produced, such as the high float residue
emulsion and the quick-set emulsion. The specifications of various asphalt
emulsions are standardized by ASTM D977.

T ABLE 9.7 Asphalt Emulsion Grades

Setting Viscosity of Emulsion, Penetration

Charge Grade Speed Saybolt Furol at 25°C of Residue

Anionic RS-1 Rapid 20-100 100-200

RS-2 Rapid 75-400* 100-200

MS-1 Medium 20-100 100-200

MS-2 Medium Ú 100 100-200

MS-2h Medium Ú 100 60-100

SS-1 Slow 20-100 100-200

SS-1h Slow 20-100 60-100

Cationic CRS-1 Rapid 20-100 100-250

CRS-2 Rapid 100-400 100-250

CMS-2 Medium 50-450 100-250

CMS-2h Medium 50-450 60-100

CSS-1 Slow 20-100 100-250

CSS-1h Slow 20-100 60-100

*Test at 50°C