1. Asphalt Materials

2. Asphalt - Definition:
“A dark brown to black cementitious material in which the predominating constituents are bitumens which occur in nature or are obtained in petroleum processing.”
(ASTM D Standard Terminology Relating to Materials for Roads and Pavements )

3. Asphalt Types Natural asphalt deposits
Natural evaporation of volatile portions of petroleum leaving the asphalt fractions
Lake asphalt
Trinidad
Bermudez
Rock asphalt
Natural asphalt deposits in porous rock

4. Asphalt Types Petroleum asphalt
Produced through the process of distillation of crude petroleum
Accomplished by raising the temperature of the crude in stages
Different fractions separate at various temperatures
Lighter fractions - Simple distillation
Heavy distillates - Vacuum distillation, solvent extraction

5. T E M P R A U (F) PERCENT DISTILLED 1000 900 800 700 600 500 400 300
200
100 10 20 30 40 50 60 70 80 90
ASPHALT
GAS OIL T E M P R A U
(F)
DIESEL
KEROSENE
GASOLINE
GAS
PERCENT DISTILLED

6. Asphalt Types
Refining produces asphalt with specific characteristics for varied uses
Paving asphalt
Roofing asphalt
Other special uses

7. Asphalt Types Paving asphalt Asphalt cement Cutback asphalt
Emulsified asphalt

8. Cutback Asphalt Precautions
Application temperatures are often higher than flash point!
Do not load hot AC into tanks which contain cutback asphalt

9. Emulsified and Cutback Products
Slow
Curing (SC)
Cutbacks
Road Oils
Rapid
Curing (RC)
Cutbacks
Medium
Curing (MC)
Cutbacks
Asphalt
Emulsions
WATER
AND
EMULSIFIER
GASOLINE OR
NAPHTHA
SLOWLY &
NON-
VOLATILE
OILS
KEROSENE
ASPHALT
CEMENT
ASPHALT
CEMENT
ASPHALT
CEMENT
ASPHALT
CEMENT
Emulsified and Cutback Products

10. Asphalt Emulsions
A suspension of small globules of one liquid in a second liquid with which the first will not mix: an emulsion of oil in vinegar
Major uses
Surface treatments
Patching
Stabilization
Slurry sealing
Recycling

11. Asphalt Emulsions Factors which increased usage
Energy crisis of 1970’s
Petroleum solvents not required
Used without additional heating
Reduced atmospheric pollution
Ability to coat damp aggregates
Variety of emulsion types
Economical - less fuel consumption

12. Asphalt Emulsions Emulsion technology
Using mechanical and/or chemical processes to combine two or more materials that would not mix under normal conditions
Emulsions used today were developed in 1920’s Mayonnaise, paints, hair dyes, ice cream

13. Asphalt Emulsions Anionic Grades Cationic Grades RS - Rapid Setting
MS - Medium Setting
SS - Slow Setting
Mixing ability
RS grades do not mix well with aggregates
MS grades mix well with coarse but not fine aggregates
SS grades mix well with fine aggregates
Cationic Grades
CRS - Rapid Setting
CMS - Medium Setting
CSS - Slow Setting
Asphalt Institute Basic Asphalt Emulsion Manual MS-19

14. Asphalt Emulsions Composition Asphalt cement Water Emulsifying agent
May contain a stabilizer

15. Asphalt Emulsions
Breaking - Separation of the water and asphalt globules
Asphalt Globules
Water and
Emulsifying Agent

16. Typical Emulsion Nomenclature
CRS-2P
CLASSIFICATION
PREFIX
MODIFICATION
SUFFIX
SUB-CLASSIFICATION
VISCOSITY SUFFIX

17. Asphalt Emulsions Emulsion must be stable
Asphalt particles remain in suspension
Pumping
Prolonged storage
Mixing
Emulsion should break easily
Contact with aggregate in mixer
Sprayed on road surface
After cure, asphalt retains original properties

18. Asphalt Emulsions Classification Anionic
Negatively charged asphalt particles
Cationic
Positively charged asphalt particles
Dependent on type of emulsifying agent used

19. Asphalt Emulsions Factors affecting breaking and curing
Absorption rate of aggregates
Aggregate moisture content
Aggregate gradation - surface area
Weather conditions - temp, humidity, wind
Type and amount of emulsifying agent
Intensity of aggregate charge
Mechanical manipulation and rolling

20. Asphalt Emulsions Storage and handling
Store between 10° and 85° C (50° and 185° F)
Use tall, vertical tanks for storage
Do not used forced air to agitate
Do not mix anionic and cationic grades
Do not dilute RS grades with water
MS and SS grades can be diluted
Add water to emulsion slowly
Do not add emulsion to tank of water
Do not add hot asphalt cement to emulsion tank

21. ASPHALT PLANT

22. Asphalt Plants Stationary plants At a permanent location
Often times materials are hauled to the plant from other sources
Portable plants
Moved from location to location
Take advantage of aggregate sources close to the job site

23. Asphalt Plants Items common to both plant types Site location
Aggregate storage and cold feed system
Aggregate drying and heating
Dust collection system
Asphalt storage tank(s)
Plant control facility

26. Cationic emulsions are preferred for acidic aggregates and anionic emulsions for basic aggregates