Asphalt Cements, Cutbacks, and Emulsions

Asphalt Binder

* Penetration (D946) Lower number,

harder binder 40-50 Pen, 60-70

Pen, 85-100 Pen, 120-150 Pen, 200-300 Pen

Asphalt Binder

* Viscosity (D3381) Lower number,

softer binder Original, AC 2.5,

AC 5, AC 10, AC 20, AC 30

Aged, AR-1000, AR-2000

Asphalt Binder

* Performance Graded (PG 64-22) Based on expected in-service

conditions Graded to resist three main distress

types Sophisticated system, more equipment

and training

Asphalt Binder

Emulsions

* Mixture of asphalt, water, and emulsifying agent

* Different emulsions can be made with the same base asphalt (type and amount of emulsifier)

Water and emulsifier

Asphalt droplets

Emulsions

* Colloid mill Small asphalt

droplets form Electrically

charged Asphalt

suspended in water

Emulsions

* Anionic (-) (D977) Rapid set (RS) Medium set (MS) Slow set (SS)

* Cationic (+) (D2397) CRS CMS CSS

* High float (HF) * Harder base (h) * Non-ionic * Quick set (QS)

Special applications

Emulsion Handling

* Storage * Vertical tanks, gentle agitation, slight

heating * Avoid water-no boiling, steam, etc. * Avoid contaminants-hard water, oil,

other emulsions

Emulsion Handling

* Break Evaporation Surface contact Temperature Chemical

Emulsion Mixing

* Aggregates have surface charges Gravel (-) Limestone (+)

Cutbacks

* Cutter stock is added to the asphalt * Rapid curing (RC)

Cut w/ light ends RC-70, RC-250 Tack, surface treatement

* Medium curing (MC) Cut w/ kerosine MC-30, MC-70, MC-250 Prime coat, road mixing

Cutbacks

* Slow curing (SC) Cut w/ diesel SC-70, SC-250, SC-800 Stockpile mixtures, dust pallative

* The lower the number, the more cutter added and the more fluid the product * RC-70, RC-800; MC-30, MC-3000

Cutbacks

* Cutbacks are used less and less in the United States Environmental concerns Energy waste (loss of high end product) Safety Application temperature