Presentation is loading. Please wait.

Presentation is loading. Please wait.

A Asphalt Materials. a Asphalt - Definition: “A dark brown to black cementitious material in which the predominating constituents are bitumens which occur.

Similar presentations


Presentation on theme: "A Asphalt Materials. a Asphalt - Definition: “A dark brown to black cementitious material in which the predominating constituents are bitumens which occur."— Presentation transcript:

1 a Asphalt Materials

2 a 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 D8 - 02 Standard Terminology Relating to Materials for Roads and Pavements )

3 a 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 a 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 Asphalt Types

5 a T E M P E R A T U R E (F) PERCENT DISTILLED 1000 900 800 700 600 500 400 300 200 100 0 0102030405060708090100 ASPHALT GAS OIL DIESEL KEROSENE GASOLINE GAS

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

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

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

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

10 a 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 a 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 Asphalt Emulsions

12 a 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 Asphalt Emulsions

13 a Anionic 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 Emulsions Asphalt Institute Basic Asphalt Emulsion Manual MS-19Basic Asphalt Emulsion Manual

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

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

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

17 a 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 Asphalt Emulsions

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

19 a 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 Asphalt Emulsions

20 a 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 Asphalt Emulsions

21 a ASPHALT PLANT

22 a 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 a 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 Asphalt Plants

24 a

25 a

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


Download ppt "A Asphalt Materials. a Asphalt - Definition: “A dark brown to black cementitious material in which the predominating constituents are bitumens which occur."

Similar presentations


Ads by Google